my friend doesn't have the iphone plan but has the iphone 3g he bought off someone and he does have a contract with at&t. but with some regular phone. can he just pop in the sim card from his old phone into the 3g? will at&t detect his sim is in a 3g and automatically make him add the iphone plan to his contract? or is he free to use the phone like a regular phone. (no 3g capabilities of course) it's an iphone 3g 3.0 jailbroken edit: if they can automatically detect it and add the iphone plan to your contract. does it being jailbroken prevent the detection?