I have a 3GS and I upgraded to 4.0 today. After the upgrade my phone will only work on wi-fi. I can make calls regularly and text but can not use any apps, check mail or surf the web. The 3G sign is showing so my phone is working properly but it cant do anything but make a call or text. Please Help!

i did the dfu restore and the only the phone is stuck with an apple logo and a status bar underneath. My itunes said it couldnt restore the phone. Help!