Can I use my old iPhone on Verizon Wireless?

No, your old iPhone won't work with Verizon Wireless. Current AT&T Mobility iPhone models, including the original iPhone (2G), iPhone 3G, iPhone 3GS and iPhone 4 are all GSM devices, not compatible with Verizon's CDMA network.

To launch an iPhone that works on the Verizon network, Apple has manufactured a new CDMA-compatible device.