At this stage, with both boys, I went to extreme efforts to *prevent* naps from occuring after 3pm. Often this meant no nap at all. There was a 3 week transition period where they seemed *so* tired and miserable all the time, and then they suddenly adjusted. It was worth the 3 weeks of temporary misery.
The "Jim somebody" who does story tapes is "Jim Weiss." He's wonderful. "Goodnight Stories" is particularly great. Relaxing, calm 10 minute stories interspersed with 5 minutes of soothing music, for an hour.
I also find that staying in the room becomes a distraction at some point. With our son (who is 6!) I am finally learning that its important though, to give him time to talk out all his thoughts before I expect him to sleep. So I sit with him and nod, and smile, and listen while he talks and talks and talks -- and eventually he gets it all out and finds it much easier to relax. I *really* wish I had figured this out about him years ago.

For so long I've been telling him to STOP talking, and hold still, and be quiet -- thinking to myself that he can't fall asleep until he does those things! But really he needs a "buffer zone" between awake-time and asleep-time, when he can get all this out of his system.