have at&t change anything.? Looking to buy a iphone 3gs. I have a motorola atrix 2 4g. Can i just swap the sim from my motorola to the iphone and get all the functions considering i already have a data plan. Or do i have to contact at&t and tell them i now want to use a iphone and so on and so forth. Thanks for any help, need all i can get before i make my purchase.