The "Reset Network Settings" button on the iPhone not only resets your Wi-Fi settings -- resulting in a clean slate with respect to Wi-Fi access points and their passwords -- it also resets your phone carrier settings. Several months back, I had the darndest trouble with cellular data access. I could place and receive calls, but couldn't get cellular data access no matter what I did. I tried going into and out of airplane mode, turning the phone on and off, and resetting it, all with no luck.

So I decided to call AT&T. Apparently, one of the cell phone towers near my office was having trouble and fell out of and back into commission. And although the tower was back up and running, my iPhone was stuck in cellular data purgatory. AT&T support suggested that resetting the network settings on the device would likely resolve the issue: and it did. Resetting network settings has also helped me resolve an issue I was having with Visual Voicemail on another occasion.

To reset your iPhone's network settings, tap your way to Settings > General > Reset > Reset Network Settings. With great power also comes great annoyances, like having to reconnect to previously remembered access points and having to re-enter passwords.

If you checked for updates for your US-based iPhone in iTunes in the last day or two, you should have seen this:

The standard Apple explanation from the Knowledge Base:

iTunes 7.7 and later has the ability to update the carrier specific settings on iPhone with iPhone 2.0 software or later. Carrier settings updates are small files (about 10k) that are downloaded from iTunes to be installed on your iPhone. The carrier settings can include updates to the default APN (how iPhone accesses the carrier's cellular data network), special dialing codes at Settings > Phone > [Carrier] Services, default settings for Stocks, Maps, Weather, and other items.

So what's actually in this update?

Logo replacements, apparently, for AT&T's upcoming MicroCell service (at the time of this writing, the page is in maintenance mode). 2 images, light and dark versions of the image on the left (courtesy of MobileCrunch). Commenters at The iPhone Blog also confirm the revised connectivity image. Our own commenters note that Apple has added settings for the Mobily network (Saudi Arabia) and Etisalat (United Arab Emirates) in this update as well, which adds weight to the expected 2/15 launch of the iPhone in those countries.

Editor's Note: Canadian and European customers report no carrier update for them, which is understandable considering the AT&T-centric content of this update. To all of our international readers, if we got you all excited about this update, our apologies for your disappointment. With the exception of Jason, we don't have non-US iPhones to test with, so we often can't say for sure whether a specific update is universal or domestic-only.