Virgin Mobile iphone 4s: Does it work on T-mobile?

If I purchased the unlocked iphone 4s from Virigin mobile would I be able to use it on T-mobile? Does anybody know if the virigin mobile iphone has a spot for a sim card like the ones T-mobile uses?

It is not unlocked if you buy it through Virgin. Virgin uses CDMA technology and runs on Sprint's network (which also uses CDMA). T-Mobile uses GSM. The two technologies are incompatible with each other.