So I recently got an AT&T contract with a Family plan for my fiancee and I, and I have an iPhone 3G at the moment - this is around Jan of this year (09) that I signed up. Of course, I do want the iPhone 3GS, and as it is... it's much too long to wait for a good price, so my parents have offered to do something, and I wanted to make sure this would work. My mother wants my 3G. This is no problem, I can jailbreak, unlock, whatever she wants. She offered in return to get a 3GS for me under her awesome upgrade price. Remember - these are two separate A&T accounts. My question is this: Is it possible for her to purchase the 3GS as is, send it to me, and will my AT&T SIM work in it without any problem? Just curious. I've tried searching for the specific answer and only found questions answered pertaining to people under the same account umbrella. I don't know if applies outside of that. Much thanks.