[tacotoy]

GSM and CDMA are 2 different types of technologies and use different frequencies. The hardware is literally different between the 2 devices to make them function on their respective networks. Sprint and Verizon offer "World Phones" that operate domestically on their own CDMA networks, and then have a GSM radio also that allows it to operate on internationally GSM networks. There are hacks and modified radio drivers that allow these World Phones to use GSM networks domestically. The GSM providers dont make any devices really that go the other way.