This question may have been asked a few times already but I've been impatient and can't really get a clear answer... I am currently a GoPhone customer with AT&T and I was wondering if I buy an iPhone, would I be able to transfer my sim from my old phone to the iPhone and have it work properly? If it does work, could I add the Unlimited Data ($19.99) and Unlimited Text ($19.99) to my $49.99 plan? I hope I made this kind of clear, but if not let me know. I really want to figure this out before I buy my iPhone next month. Thanks for your help!