[dansamy]

If the new phone is not an At&t phone, it will need to be "unlocked". The best source for cheap, unlocked phones is eBay. Just make sure you use a reputable seller. My suggestion? Cheap At&t prepaid and put your SIM in it. Sell the prepaid SIM and airtime on eBay and recoup some of your expense. Sprint doesn't use a SIM-based system. They are CDMA and the user info is programmed by Sprint and attached to the phone's EIN. SIM-based cell phone companies program the user info and link it to the SIM card's EIN.