Hi! Someone gave me their old iphone when they bought a new model. The one they gave me is one of the very first ones they sold, he stood in line and got one the day they came out. And of course he paid a lot of money for it. Silly. Anyway.. So now he has a new one. He took his SIM card out of his old iphone and put it in the new one and he was good to go. So I have his old phone but it has no SIM card in it. He told me I can put my SIM card from my Nokia in it and use it on Centennial Wireless after I "jailbreak" and "unlock" it. I have found software for doing that but the thing I don't understand is, do I have to have an AT&T SIM card first to do all this? Or can I just pop mine in then do all the unlocking/breaking stuff and be good to go? I've never messed with SIM card stuff or phone hacking before. I'm sure I can do it but I just want to know if I can do it without having his AT&T SIM card? Thanks so much!