Seems like quite a few people are seeing this issue over at the Apple support forums. I had it happen to my 3GS but not my wife's. After the upgrade which went smoothly I could get no internet via 3G or Edge only via WiFi. I checked all the settings to make sure 3g data was on and even tried turning it off then back on but nothing. I did a restore to factory and then restored from a backup but same issue. The final thing I tried was a fresh restore and didn't restore from a backup but left everything stock and that worked. I am currently reinstalling all my apps and re-setting up the phone. Just an FYI for anyone else that runs into this issue, restore to fresh phone and do not restore from a backup but re-setup everything instead.