I was able to activate my phone but no matter what I try my phone will not give me any reception. I tried turning off all the push services and still nothing. Did a complete restore and nothing. Any ideas on how to get my reception.
I was in this same boat - it was a SIM card problem...took it back to the AT&T store where the swapped out the SIM and did something on their computer networks and now it works.
Call AT&T and tell them you need to know what SIM card is registered to your account. Then just pop out the SIM card that came with your new iPhone and tell them that number and have them switch it. My iPhone works now because of that.