Be prepared for a long phone call with AT&T. Some reps apparently aren't too informed about the unlocking process. When the crew at WPCentral called AT&T about unlocking a Nokia Lumia 900, they spent 33 minutes on the phone trying to explain to the rep on the other end of the call, what they wanted to do to the phone. When everything got resolved, it turned out that the carrier had lost the unlock code which should be received on October 17th.
Last month, we told you that AT&T had put online a form to make unlocking an out of contract Apple iPhone a lot easier and quicker. We might see that eventually for the Windows Phone powered Nokia Lumia 900, but for now, unlocking the flagship Nokia device requires you to make a phone call.