I used to have that problem...
Try running/walking for 20-30 minutes in the evening. Not only will you lose weight (Thats why I started), but I find that just that bit of exercising makes it SO much easier to sleep. I went from needin anywhere from 3-6 hours (I quite frequently got 3 hours of sleep) to 30 minutes to an hour to get to sleep.
Just an idea, if you don't feel like chugging pills.