J.H.
Do you mean you have cable TV in his room? TV in a child's room (even a teenager's) isn't a very good idea. I know that if I watch TV right before bed, the fast edits and flashing pictures that are so common in today's shows often stimulate me and make it hard to fall asleep. Excessive TV viewing can contribute to poor grades, sleep problems, behavior problems, obesity, and risky behavior. See: http://www.med.umich.edu/1libr/yourchild/tv.htm and http://www.wholefamily.com/aboutyourkids/child/television....
Try reading a good book together at bed time. If he's still napping in the afternoon, it might be time to shorten those or get rid of the naps too, to make bedtime easier. Hope this helps.