Can iphone 4 be for at&t prepaid?

My little sister has prepaid at&t phone, she is getting the iphone4. But sense the sim cards are smaller for the iphone4 than any other phone how would she fix the problem? Could we go to at&t to get a new sim card?

If you go on Google or YouTube they teach you how to cut your sim card. And at&t will not give you a new card cause iphone don't have prepaid

Hmm, I think that you'll have to buy full retail for the phone which should be $550 plus tax.