I want to buy an iPhone off amaZon for virgin mobile, will this one work?

Apple iPhone 4 32GB (Black) - Verizon http://www.amazon.com/...004ZLV5VS/

Many older model Verizon iPhones will not work on other networks. The newer ones will

Actually, none of them will. CDMA requires the phone be "flashed" to work on any other carrier. The control firmware has to match the carrier, and that includes an iPhone 4. You can probably find a local fly-by-night shop that can do the flash to Virgin, but there's no other way to make it work.