LegallyKim,
I've often wondered the same thing on how to get them moved to their own bed. Especialy after the night I woke up with a black eye because Liam managed to turn sideways, between our pillows and whacked me in the eye with his heel!!!
I love co-sleeping with him, but occasionally feel like his is much more in charge then I would like. but I wouldn't give up cuddling him to sleep for anything. So I guess I'm torn.....
The only suggestion I've ever heard for transitioning them to their own bed is that they will eventually go there on their own. Not much of a suggestion..... but I've never heard of a 15 year old co-sleeping with his parents, so it must magically happen some how!!