I think it may vary from college to college; at mine there was a cap on how much you could upload per day, but nothing on downloading. The actual content didn't seem to be monitored either. My whole 4 years I basically just used BitTorrent and sometimes WinMX, and there were never any problems. Some people I know got briefly kicked off if they uploaded too much per day, but they could just go down to whoever runs the school network and get back online with a warning.
Again, it might depend on your school though, and whatever their policy is about this. It's usually fairly easy to find out from someone there.