Well, here is my current situation. I currently have a iPhone 3G but just recently cracked the screen. I activated it through AT&T and use its service so it is not a jailbroken iPhone. My friend has a iPhone 3G (also not jailbroken) as well and wishes to sell it because he bought a BlackBerry. As I am not inclined to buy a new iPhone for $500 from AT&T, I would much rather buy this one for $200. Can I switch my iPhone 3G's sims card (which is activated) into his iPhone 3G and have it work? Will I run into any problems when I sync all his data off and replace it with my own from my old iPhone's backup? Also, as I forgot which iPhone 3G he has (8GB or 16GB), but does it matter which type it is for it to work? For example, I have a 8GB version and say he has a 16GB version, would it work fine if I were to swap sims cards (but that brings up the question does it work at all to swap sims cards)? Thanks for the help!