Apple released updated iPhone software, version 3.1.2, this very afternoon. The previous version was 3.1 and no I don't know what happened to 3.1.1. This update takes a lot less time than the 3.1 version and it is supposed to help the iPhone to wake up from sleep more reliably, to connect to the AT&T cellular network more reliably, and to show video without crashing more reliably. I never saw any of those problems but I guess someone did, and the new software is here to fix it.
Assuming you want the update, which is free, all you do is connect your iPhone to your computer with the USB cable, wait for iTunes to launch, click on your iPhone in the left-hand side of iTunes, and then "Check for Update." It's a big button-- you can't miss it-- and it looks like this:
Click it, follow the directions, and you're all set. You will be asked at the end whether you want to update your carrier settings, and you do.
The whole process took about half an hour for me, and my iPhone seems to work at least as well with this update as it did without, so I say go ahead and do it.
