Will a sim card from tmobile work in a Virgin Mobile iphone 4s?

The virgin mobile iphone 4s has a sim card slot, so if i put a tmobile sim will it work? If the iphone isn't activated with a virgin mobile. Or if i buy a iphone 4s from the apple website without any service will it work with virgin mobile?

If you buy a contract free iPhone from the official Apple store you should be able to use any active SIM that will fit the phone. The iPhone does cost a lot so I'd go to a local store or call customer service before I buy the phone just to be sure it works.