Actually, you can activate most Sprint phones on the VZW network. Both carriers use CDMA technology. rita@aol, you will need to take the iPhone to a VZW store to determine compatibility for certain.
Agree with Tidbits
Sprint locks their phones and Verizon will not add the IMEI into the Verizon database. Since the CDMA iPhone 4 has no SIM card, there isw no option for that. So in full summary It will not work, not at all.