L.O.
I had the same problem getting back to sleep. My problem was that I couldn't shut my brain off after waking up. I just kept thinking about everything I had to do the next day. I bought a relaxation CD off itunes and now I use my ipod to get me back to sleep. The one I liked the best was Guided Relaxation for the Body and Mind. It puts me back to sleep before its over and it is about 20 minutes long. I keep the volume low enough so that I can still hear my little ones if they need me.
Good luck!