Last semester, I had an intern who asked me what she could do to "green" her dorm room. Sadly, the only thing that readily came to mind was change your light bulbs, don't leave your appliances on or plugged in when not in use, and that was really it. I just happened across a great article on PlanetGreen today on "How to Go Green: Dorm Rooms." This will give you a few more ideas!
Check it out: Go Green: Dorm Rooms