The easiest way is to light the background, not the subject and meter for the background. It's really not all that different than doing it outdoors, it's just that you have to position the light(s) and make sure it's strong enough so that it does make your subject very dark. Obviously, this will work better if the background is very light in colour and there is no other ambient light. Also, be aware of the room size and light bounce, if the room is small, you may still end up lighting the subject more than you want.
To answer your specific question, if the subject is small enough, a flash behind diffusing material, which is behind the subject, may do the trick for you with the diffusion material acting as the background. But if the subject is a person, it may be more difficult to do with a basic flash. Also, if you're remote controlling the flash with the onboard popup, make sure the onboard flash doesn't fire or you shield it.
If your light source isn't continuous, you may have to do a few test shots to get the exposure right. Which, with digital, isn't really a problem. :)
Anyways, if you get very close, you may be able to complete the effect in post processing with some exposure, curves, or black level adjustments if you shoot RAW (which I always recommend anyways).