What worked for me when I had a similar problem was my clock radio. I bought a pillow speaker and turned on a talk radio show at a very low, muffled volume. (Note: your radio must have an ear phone jack). Invariably I would fall asleep w/in 10 or so minutes. This technique has only worked for me with the speaker; a radio itself would not get to a low enough volume, and when commercials came on I would awaken.
Many electronics parts stores sell pillow speakers...I know Radio Shack does.
Good luck.