So.. My family of six each have phones in AT&T. Last year, I used my upgrade and got the iphone 3g. This year, my dad offered to buy my 3g from me and have me get the 3gs. I definitely took him up on this deal. I just ordered it, but had to use my brother's number in order to get the upgrade (it was the only one available..no one else had an upgrade available) My question is, when this new iphone 3gs ships to my house in a week... will i be able to use it with my current 3g SIM card?? And- will my dad be able to stick his current SIM card into my old iphone 3g?? NOTE: The iphone 3gs came with my brother's number.. does that matter?? Thanks for your help!