I got my iphone used from someone on craigslist... The phone still had an activated sim card in it... I went to att and got a new sim... When I put it in and connected it to itunes I got an error that this phone was not able to be activated for service.... So I though it was because it was still active so I used iPhone interface to deactivate and try but nuttin.... So I called att and they said that the equipment was still registered to someone account and that if I can't get in touch with the account holder and have them take it off their account that pretty much I'm screwed and own a paperweight... So I tried to contact them but couldn't find the number to reach him because the post was gone already... Getting frustrated I just wanted to be able to get on wifi for the time being and used the activation medthod for old sim card users on www.hacktheiphone.com and the strangest thing happened... It worked... Much better than I wanted.... Now I have full cell phone service on andead sim card with no bill... I checked my mins and I have 450 and the balance is due 12/01/00 $0.00..... Very strange