More Mac 101, our ongoing series of tips and tricks for new and returning Mac users. If you're an iChat user with a need for immediate attention, AIM Blasts makes it easy to add social networking groups to iChat.

When you want to have a conversation with a group of people, blasts let you IM everyone in your selected group at once, without having to invite them to a special chat room. For example, you might have friend groups, work groups, or, thinking of Scott McNulty, your special D&D buddies. MobileMe users can take advantage of AIM blasts, since all .Mac and MM users are automatically AIM users as well. Just log in to AIM.com as yourname@me.com (or mac.com) -- you'll be able to take advantage of all of AOL's instant-messaging hospitality.

You don't set up your blast in iChat. Instead, point your browser at blast.aim.com. There, you'll be able to invite your friends and establish your new group. All joining and messaging is done from inside iChat itself. Blast groups appear in iChat as a separate group in your Buddies list -- scroll down in the buddy list if you have trouble finding your blast groups. It may help to give them names that are distinct from any buddy groups you already have, or perhaps prefix your blast groups with a "B-" to help them stand out.

When setting up your blast group, you decide whether all members or only admins (i.e., you) can send messages and/or invitations. Blast recipients have to accept your invite to be part of a blast group, so you may want to give them a heads-up in advance (especially if your blast group's name is obscure or edgy).

Just so you know: TUAW and Weblogs, Inc. are part of AOL.

As a Mac switcher, my Mac's built-in spelling and grammar checking has been a huge productivity boon for me. I'm someone who often gets stuck on a word, and since nothing's ever good enough for me, I've often wished that Leopard also included a built-in thesaurus. While that's not currently in the cards, there is an alternative. How many ways are there to say "Whoops?" Of course, Leopard does include a built-in thesaurus via Dictionary.app. See the continuation of this post for a screenshot. Thanks to everyone in the comments for keeping me honest.

If the Apple offering isn't to your liking, Nisus Thesaurus, a free app from Nisus Software, works as a standalone application and a system service. This means that it installs in the Services sub-menu of your Mac and is accessible from any program you use that is able to interact with the Services sub-menu. These applications include Mail, TextEdit, Safari, MacJournal, and countless others.

Once installed, using your new thesaurus is as simple as highlighting a word that you would like to look up, and pressing the Nisus Thesaurus Services sub-menu hotkey (Command -<). This will pop up the Nisus Thesaurus window with your word options only a click away. Select the word you would like to use as a replacement, press Command->, and voila; your new choice has replaced the original word.

More Mac 101, tips for the Mac beginner in you. Lucky dual-monitor users, rejoice -- with that second display on your desk, you're bound to be the productivity envy of the entire office. Just one little problem, though: sometimes your Mac has trouble recognizing that extra real estate, and rebooting every time your resolutions get munged is beginning to get old.

Relax, and check out your mini-menu for monitors over there in the menu bar. See "Detect Displays?" That's your buddy, right there -- it will tell your Mac to recheck the connected monitors and adjust resolutions as needed. Note the model number of the external display shown; if everything's connected as it should be, your Mac should autosense the type and capabilities of the display without any intervention.

For an even quicker trigger on display detection, try Cmd-F2 (brightness up) on your built-in laptop keyboard. Cmd-F1 will toggle display mirroring, also handy in a pinch.

There are several ways other ways to get external displays to behave; the oldest, for laptop users, is to sleep the machine and wake it back up -- this usually triggers a display detection when all else fails. There's also a Detect Displays button in the Displays preference pane.

Also, to answer a reader question from the comments: it's easy to specify which display acts as the primary monitor in a dual-display setup: just drag the teensy proxy menubar from one display to the other, and your menus, drive icons etc. will follow.

There are a handful of things I miss from OS 9, like programmable function keys (and Extension conflicts. I kid.). Just like The Apple Menu and the Happy Mac, fully customizable function keys were killed by Apple's big cats.

However, we're not at a loss. The folks at Bitbox have described the simple steps needed to get some of that old flexibility back. First, launch system preferences and click the "Keyboard" tab. Next, select the "Use all F1, F2 etc. keys as standard function keys" option.

Now, you can use your function keys as nature intended. Their specialty functions are still available, too (like volume and brightness); just hold down the "fn" key while hitting the key of your choice.

Back to basics with Mac 101, our ongoing series of posts aimed at new Mac users. If you've got a hankering for news about the latest Mac-compatible products, you've got plenty of places to look (including, naturally, right here). What if you've got a specific product need, something obscure, small-audience or somewhat vintage? You can always hit the search engines or check our archives, but there's a one-stop shop for Mac-compatible products that doesn't always get top billing: Apple's Macintosh Product Guide, tucked away at guide.apple.com.

This venerable database of Mac apps and hardware (it's under the Developer heading on Apple's site nav, and judging by the 'lasso' URLs it may run off a FileMaker back-end-- way to support the home team!) lists thousands of products, and it's got separate categories for iPod and iPhone accessories. Starting off with the guide is a great idea if you need to find a vertical-market or niche app; you'll probably come up with several good choices.

We've had some questions recently on Ask TUAW about boot options so I thought it would make for a good Mac 101. Obviously, Boot Camp has brought dual-booting to the fore on the Mac platform, but there are actually a variety of boot time options built into your Mac which allow you to interact with it to some degree before loading the OS. The most important of these, of course, is choosing the boot partition and this is easily done by holding down the option (⌥) key after restarting the machine. This will bring up a menu of all bootable volumes (such as a Windows Boot Camp partition), including mounted external USB and FireWire drives as well as optical discs. However, there are more handy shortcuts as well:

• You can force OS X to boot from a mounted optical disc by holding down the C key.
  
• Holding down the T key will put that Mac into FireWire Target disk mode, which will allow another Mac to access its hard drive over a FireWire cable as if it were an external hard drive.
  
• Holding down the Shift key will boot into Safe Mode, which can be very useful if your Mac is misbehaving.

Apple has a nice list of a few more boot time key combos that are worth keeping in mind.

For someone who loves keyboard launchers like Quicksilver, I have to confess an embarrassing deficiency in my keyboard competency: I've never really learned to select text with the keyboard. So I thought the topic would make for a nice beginning of the year Mac 101.

The keyboard text selection commands on the Mac are basically standard. To select text you hold down the SHIFT key and then use the arrow keys or HOME, END, PAGEUP, and PAGEDOWN. The left/right arrow keys (plus SHIFT) will increase the selection one character in that direction, if you hold down the OPTION (⌥) key the left/right arrows will select an entire word in that direction, and if you hold down the ⌘ key the left/right arrows will select to the beginning or end of the line. The up/down arrow keys (plus SHIFT) will select a full line up or down; with the OPTION key held down the up/down arrows will select a paragraph. The HOME key (plus SHIFT) will select all the text to the beginning of the document and the END key (plus SHIFT) will select all the text to the end of the document. Finally, the PAGEUP and PAGEDOWN keys (plus SHIFT) will select a full "page" up or down.

Basically the upshot is this: hold down the SHIFT key while in a text field and it will shift to text selection. Also, if you use the keyboard shortcuts without the SHIFT key they will move the cursor without selecting text. If you play around with and internalize these commands I think you'll find that keyboard text selection is often faster than moving your hand to the mouse. These commands can be really handy if you're selecting text in very small boxes where you can't see much (e.g. long names in open and save dialog sheets). One proviso: these shortcuts should work in all Cocoa applications, but they may not all work in non-Cocoa ones.

I've got a 4-year-old and a 2-year-old, so Photo Booth is a big hit in my house. They love to mug for the camera and send silly snapshot to grandma and grandpa. I've used it quite a bit, and thought I knew all the tricks.

This morning, Macsupport has pointed out a few new ones. First, you can disable the countdown if you want to snap a photo immediately by Option-clicking the shutter button. Shift-click to disable the flash and finally press both the option and shift key to immediately snap a photo with no flash.

These tricks seem to be unique to Leopard.

We've talked previously about the wonders of the Application Switcher, the translucent bar that comes up when you hit ⌘-Tab. However, thanks to Macworld I realized today that the Leopard version adds a great feature that should have been there a long time ago: drag and drop. In Leopard the application icons in the Application Switcher are live. This means you can grab a file in the Finder, hit ⌘-Tab, and drop the file on the running application of your choice. So, for instance, you can easily drop a plist on a text editor instead of using the default plist editor. In previous versions of OS X you needed LiteSwitch X ($14.95) to achieve the same thing (though it's true that LiteSwitch X still has a few tricks up its sleeve that the default Application Switcher is missing).

So far as I can tell, practically everybody loves Leopard's Quick Look previewer. For today's Mac 101 I thought I'd share a few tips about using Quick Look.

• First is nice little tip from Mac OS X Hints about zooming in Quick Look. If you invoke Quick Look with the spacebar you can actually zoom in on the image in a couple of ways. You can hold down the option key and use your mouse's scrollwheel/ball (or two-finder scrolling on a touchpad) to zoom in and out. You can also zoom in by holding down the option key and clicking on the image, or zoom out by holding shift-option. While zoomed in you can also click and drag to pan the image. Strangely, the same shortcuts don't work with PDFs, but you can still zoom in and out with ⌘ + and ⌘ - (command plus/minus) with the Quick Look HUD selected.
  
• The second is that you can use Quick Look with more than one file at a time. So if you select several files in the Finder by command-clicking and then invoke Quick Look with the spacebar, you can scroll between the images with the arrow keys. However, there's also a nifty index sheet icon at the bottom that will bring up a kind of contact sheet with the selected files (as above).
• Finally, I know some folks had complained that the slideshow option has disappeared from the Finder's contextual menu. But if you select a group of files in the Finder and then invoke Quick Look you'll also see a play button that runs a slideshow in the Quick Look HUD.

For today's Mac 101 I thought I'd draw your attention to a feature of the Displays tab of the System Preferences that only appears on external monitors: Rotate. If you plug in an external monitor to your Mac you should see that you have the option to rotate the display by 90 degree increments (clockwise). Now why would you want to do this? Well, if like me you have an external widescreen display, sometimes it's actually more handy to use it vertically instead of horizontally. I do this because I work entirely on the main (24") display and use the external (20") for showing my email, iTunes, etc. On my desk, I feel like this is a more efficient allocation of pixels. You can see a picture of my setup after the jump.

Leopard may be just around the corner but we're not ignoring you readers who aren't ready to upgrade. Here's a quick tip for those of you who plan on staying in Tiger land. Sometimes you want to view pictures by previewing them directly in Finder. To automatically view the largest possible preview, just double-tap the column resizing handle at the bottom right of the preview image. This automatically maximizes the picture without affecting your other columns.

It's no surprise to most Mac users that you can use arrow keys to navigate through Finder windows. Arrow-key presses work in all three window styles: icon view, list view and column view. What many new Mac users don't realize though is that there are Command versions of these arrow keys.

When viewing folders using icon view or list view, both Command-Up-arrow and Command-Down-arrow play a special role. Command-Up-arrow moves you up to the parent folder of the currently-displayed folder. So if you are in, say, /Users/ericasadun/Pictures/Family, Command-Up-arrow would take you to /Users/ericasadun/Pictures. Press Command-Up-arrow again and you move to /Users/ericasadun. You can check your current folder by command-clicking the icon at the top of the folder window.

Command-Down-arrow only works when the selected item is a folder, and, like Command-Up-arrow, only in icon and list views. Pressing Command-Down-arrow opens and selects the current folder. So it essentially does the opposite of Command-Up-arrow. It moves you further down in the folder hierarchy as opposed to Command-Up-arrow which moves you up the folder tree.

These are useful shortcuts to have at hand when you prefer to use the keyboard to navigate through your files rather than the mouse.

More Mac 101, the TUAW answer to the unasked questions of novice Mac users. You've certainly seen the little house in your windows, but do you know who lives there? You do -- at least, your stuff does, and if Carlin said it that's enough for me.

Unlike Mac OS 9, which pretty much let you put your files and programs wherever you wanted as long as you left System and Finder inside the System Folder, Mac OS X has certain expectations regarding paths, the hierarchy of folders leading to a particular spot on your startup disk. The distinction between your personal files -- your documents, music, email, bookmarks, preferences & settings -- and everything else that helps your computer run can be stated simply: if it's in your Home folder, it's "your stuff," and if it's outside your Home folder, it's universal to the computer (or it belongs to your spouse/kids/etc.).

To get to your Home folder quickly, you can click the house icon in the sidebar of any Finder window; choose "Home" from the Go menu in the Finder, or hit Cmd-Shift-H. Once there you'll notice a few folders, including Documents, Desktop and Library. You may think "I don't like books. Why do I need a whole folder for a Library?" and be tempted to tuck it away in a "Misc" or "Stuff To Throw Out" folder. Don't be surprised, if you do, that you can no longer log into your computer -- Library has to stay exactly where it is, since it contains all your preferences and application settings. Likewise, there are some folders in Documents that have to stay put, particularly (if you use Microsoft Office) the Microsoft User Data folder.

Other than the preconfigured folders, your Home folder is pretty much yours to manage as you choose; you aren't limited to storing documents in Documents. Need a folder for Projects? Go ahead and make one (Cmd-Shift-N for a new folder), just don't get funky with the original items unless you know what you're doing.

One more tip on home folders: sometimes you'll see the notation "~/Desktop" or something similar in documentation for software, telling you where files will be installed. That "~" (it's called a tilde) is UNIX shorthand for the active user's home folder -- it expands to "/Users/myname/" when used in the Terminal, and whenever you see it you should assume it's talking about the place for your stuff.

The Keychain on your Mac is a little application buried in the Utilities folder in your Applications folder. I say buried because I think Keychain is sadly neglected by most users. Here are some things you can do with it:

• Save web page passwords
• Save login info (aside from websites, like your IM logins)
• Save protected notes (secret stuff)

This 101 will be a little longer than usual, so I can show you how to use Keychain to store passwords and other secret things. Later, in our Secure Your Mac series, we'll talk about making a good password so all these things stay private. Full details on how to easily use Keychain after the jump.