Have you tried melatonin? I also read on these boards that supplementing with magnesium helps sleep tremendously. I know I sleep a lot deeper on it.
Establishing good sleep patterns is also behavioral as much as anything else. Make sure you don't do anything in your bedroom/bed except for sleep, so you build the association. Try to finish workouts at least a few hours before going to bed, that can mess up some people's sleep schedules. Don't watch TV/go on the computer very late a night.