i have a iphone 4 i was wondering how do i used it as a pre-paid service. (1)im using pre paid service right now thru at&t (2)my sims card is opening because i can used it in other att phone but not the iphone 4 cut it down to size but it didnt work(3)just receive my new micro sim card n the mail today and was wondering how do i get it to work and can i used my same number (4)read different post and still dont no wht to do any help will be appreciate thanks 4 your time