I'm not a cell phone guru, but it's something like this: 3G is a "standard" (not an official one IIRC) of how fast data transfers are on a cellular network. If a phone is 3G capable, it supports these faster speeds. The GSM spectrum is divided into different bands, depending on where you're at in the world. Eg, a phone that gets 3G service in the US most likely won't get 3G service in Europe. On the flipside, you can get 3G speeds on CDMA networks (VZW is CDMA) but it's more commonly referred to as EV-DO. 3G is just a measure of potential speed for the most part.