Here is my setup; I had a Motorola RAZR as an exiting customer of AT&T, and bought my iPhone at the AT&T store. When I got home and plugged in my iPhone I didn't receive any activation screens with iTunes. Tried the reset functions, etc. and nothing worked. Just got off the phone with Apple tech and they had me place my old SIM card in the iPhone, and my phone got activated within 60 seconds. Weird! They have no idea why this is happening, but it may work as a solution for those that are having similar experiences.