Simply put, I just went onto YouTube and typed Relaxing music.
Here is a list of most of the ones that doesn't turn into dance/chillout songs.
http://www.youtube.com/watch?v=yrgGp2jaafs (no idea if you'll like the running water in the background, didn't do it for me)
http://www.youtube.com/watch?v=4UlZyuFiGks
http://www.youtube.com/watch?v=8DXLmnaNOAo
http://www.youtube.com/watch?v=PEulyxBCA6c (the birds chirping in this one didn't do it for me either, perhaps a wake up song rather than sleeping)
Also try some songs by Sigur Rós. I find them completely relaxing even if I don't understand what's being sung.
Svefn-g-englar : http://www.youtube.com/watch?v=zQ5Grncdjlc
Glósóli : http://www.youtube.com/watch?v=doc1eqstMQQ
Andvari : http://www.youtube.com/watch?v=55jBkNcrI_8
Njosnavelin : http://www.youtube.com/watch?v=-TXV0wAivRQ
And of course Hoppipolla - http://www.youtube.com/watch?v=PDxMQaMqsig
Hopefully these help you sleep better.