I had this problem with my 3G, wonder if anyone has had similar: Had a contact, had a address book entry and a photo. When they called me, the phone was ringing their end, but iPhone screen did nothing. When the got voicemail, the screen would light up and inform me of a missed call. If I tried to ring the contact, all is working as normal on my phone, but when i press End Call, nothing happens. if i go out of the call menu (press home button) it says Press to return to call as normal, and if you press it, nothing happens, so was no way to hangup appart from force phone reboot. I tried removing the contact, dialling without it being in address book, re-adding into address book and also a complete factory restore and restore from backup, but still the same happened. The only way i could fix the problem was to restore iphone and not use my backup. Would like to add that this had nothing todo with the iPhone 3.0 firmware. Just thought I would see if anyone else has had anything similar at all?