So I just recently got my iPhone 4 and I want to give my old 3G phone to a family member of mine. However when we put in the sim card it'll automatically add a data plan and AT&T will bill for that.
Is there a way we can hack the phone (it is jailbroken) to be able to use the AT&T SIM card just like a regular phone (call, texting) and not have AT&T know its an iphone and automatically add a data plan?