Today is Data Privacy Day, a global initiative to highlight information security rights and practices, especially among teens, professionals, corporations, and the government.

As part of the celebration, TUAW (along with our sister blog Download Squad) has seven good ideas for you about how to keep your data safe and away from prying eyes with Mac OS X Leopard. Also, be sure to browse TUAW articles filed under Security for other tips and alerts about keeping your data safe.

1: Turn on your firewall

Leopard, as we all know, comes with a built in firewall to prevent other computers from connecting to internet-facing ports on your computer. But: Did you know it's turned off by default?

To turn on your firewall, open System Preferences, and click the Security icon. Then, click the Firewall tab. Make sure either "Allow only essential services" is selected, or you can choose to "set access for specific services and applications" yourself.

You can also use "Stealth Mode": when enabled, computers that send data to blocked ports won't even get acknowledgement that the data was received. To enable Stealth Mode, click the Advanced button on the Firewall tab of the Security preference pane, and click the check box next to "Enable Stealth Mode."

2: Set a screen saver password

A feature popular with Windows users, Mac OS X can also lock your screen when your computer sleeps or when the screen saver comes on. Simply open System Preferences, select Security, and choose the General tab. Click the check box next to "require password to wake this computer from sleep or screen saver," and you're all set.

If you have automatic login enabled and click the "require password" check box, Mac OS X will recommend that you disable automatic login. This means you'll have to enter your password to turn your computer on, too; nefarious nogoodniks won't be able to restart your Mac while the screen saver is on to circumvent the need for a password. Good thinking.

If you have ever created a DMG image using Disk Utility, you know how hard it can be. iDMG hopes to make this process easier. This application allows you to easily drag and drop files, applications, or whatever you choose onto iDMG, select a few options and hit the "Create button."

The only downside to the application is the many times you encounter the slow "I am working" message. Other than that, this application offers a bunch of options like encryption, custom icons, and multiple file systems. In addition, iDMG uses the Sparkle update framework and Growl notifications.

This application is available for download as freeware (donations accepted) from the developer's website.

MurphyMac has posted a video tutorial showing how to customize your dmg containers to make them look more professional. The tutorial walks you through the steps of creating a disk image, adding a background graphic, and saving the result for production and distribution. A fully customized dmg file offers a polished presentation so you can really impress the people you're distributing your material to.

Here's a clever idea. I'll admit that I'm superficial enough to think more of a given application if its installer is on a well-designed disk image. AppZapper and Delicious Library immediately come to mind. While I simply admire them from afar, blogger Roustem Karimov is on a mission to find the best one. He has posted snapshots of several images to his blog, and he rates each in terms of appearance, how clearly information is presented and so on. Check it out, it's rather interesting.

[Via The Apple Blog]

I haven't tested this yet, but Make a Delivery sounds like a handy little Automator action that will create a .dmg file from the Finder items you have selected, then attach that .dmg to an email. One quirky thing, however, is that you have to move a resource folder into your Applications directory; it isn't just an action that you can use or turn into a right-click Finder plugin.

In any case, if you prefer an easy way to create .dmg's for emailing (instead of zip archives), Make a Delivery might be just what you need.