set up as new to fix 3G data problem
It looks like you will have to set up the iPhone as new. That corrected the problem for me and a few others in the forums.
3G not working
I had the same problem. Talked to AT&T who hooked me up with Apple. Apple said to do a restore (from inside iTunes). So I sync'd and then did a restore. 3G worked after that. I am in the process of restoring from my last backup.