Can a sprint iphone 4 be used for virgin mobile?

Can a sprint iphone 4 be used for virgin mobile?

No it can't. Directly from Virgin mobile's web site is this statement:

http://virginmobileusa.custhelp.com/app/answers/detail/a_id/896/session/L3RpbWUvMTM1ODM1ODAyMS9zaWQvdTluMkRzZ2w%3D

Use of a cell phone from a different carrier

You can't use a mobile phone from another wireless carrier, or any unlocked device.

You should be able to since virgin mobile is joined with sprint.