A friend of mine is on AT&T. She doens't want to sign a new 2 year contract to buy an iphone but she wants an iphone. Can i unlock a phone for her, just like I did for mine on USA T-Mobile and she's all set? Wouldn't AT&T realize she has the iphone and try to charge her more? Thanks in advance for you help.

I'm UK based but I never seen anyone here say thats happened on any network

So I 99.9% sure you wouldn't have that problem

you could unlock it, all you have to do is take it out the box and run iplus with the t mob sim card in and your cool, besides thats only if you go thru itunes, i would have her check her plan out and change it back incase they say she switched to the iphone plan and not her regular one but remeber no itunes activation, just hacktivation, however if she wants warrenty then have her go thru itunes then take it in

you dont need to unlock, just hacktivate it with iplus or ziphone (just do activation and JB, no unlock) and drop in the sim she is using now and everything besides visual voicemail will work just fine.

is there a problem if i do the full unlock? or should i just activate and jailbreak?

you can unlock it, no problem. I did it for a long time and I even added unlimited internet. They don't ask the model, in case they ask, just tell them you use it with your previous phone