i was already an att customer and was just moving my existing number from my old phone over to the new phone. the activation process took over 14 hours. the activation screen just said "your iphone will require more time to activate". i started it friday night and my phone wasn't activated until saturday afternoon. i called att saturday morning and they told me that everything was in place and the new sim card was activated BUT the phone itself wasn't. the only way for the phone to activate is for apple to register the phone and for itunes to send me the link. so the problems i had was an apple problem and not an att problem.