SuperNanny has shows on this all the time .. its hard once you have already established a routine, which you have. One your child has been in your room and 2 you have always left on the tv.. and you I can imagine Id have done the same, let him fall asleep then do what you can after that.
I moved my son into his room making it a big deal for him.. Started out with this is your big boy room, in your big boy bed.. nighty light on, no tv after 730pm, it only made him more active. My son just turned 5 yrs old. He is allowed to look at books, or sit quietly and color for 30 minutes prior to bed time which in our house is 8pm - he needs at least 10 hours of sleep at night. When he naps, rarely anymore, its only for 1 hour nothing more or he wont go to sleep later ..
Try a warm bath early, keeping things quiet .. no more play time, then read to him, lay with him in his room for a little bit then tell him its time for bed, then you need to leave the room. It took a long time for my son, but after a few nights of returning him to his bed until he fell asleep, he has been there ever since and he knows 8pm is bed time - no questions asked. You have to remember to keep at it and dont give in. If you give in, it only gets harder and you will have company in your room for a very long timea dn kids who know they can get away with what ever they want if they just continue long enough...
I'm with ya on this .. its hard!! Its easier to give in but if you can stick it out - its so worth it!!!
Good luck!!!
J.