Bittorrent and Bandwidth Monitoring Problem

Hey guys,

I have 5 computers at home sharing a DSL Internet connection. Each computer is used by a different person. My DSL has very low bandwidth to the point where if, for example, any of the 5 computers is downloading a music album using bittorrent the Internet slows down to a crawl on ALL computers. It feels like I'm dial-up again and it's really frustrating trying to get work done.

Now I understand that this is probably not a problem that can be remedied without switching to faster ISP but I have constantly told everyone to be considerate of everyone else and not to download anything using bittorrent. But of course no one listens and I find myself constantly playing detective trying to figure out who is using bittorrent. Its become very annoying.

So my question is, do you guys know of a basic bandwidth monitoring program that will be display the bandwidth usage of all 5 computers? I've tried a few but they either only monitor the bandwidth of my own computer or they are too complicated where a server is required. Again, it doesn't have to be too advanced, just enough to tell me who the culprit is so that I can unplug them from the router

Thanks a lot and hope you guys can help