ok so i'm buying my first iphone tonight used locally...i currently have tmobile so i need to unlock the phone...i've been reading up on jailbreaking/unlocking so i'm pretty much understanding the whole process...my question is, i'm not sure if the guy i'm buying from has updated his phone to 2.2, so if i need to update it via itunes, will i need an att sim card to do so? and if it is already running 2.2, will i still need an att sim card to jailbreak it and then unlock it? cause i don't have access to an att sim card, so i'm hoping i don't need one to unlock it...and if i do, can i just buy a prepaid one or something? thanks guys...sorry i tried searching, but couldn't find a definative answer...