I found a clock radio at St. Vincent dePaul for $1 that plays all kinds of nature noises like what Sky is talking about. It really does help.

I picked up a sleep CD at Target for $10 that has delta waves mixed in with the music, but I actually sleep worse with that than with the clock.

I have tinnitus in my right ear, and it helps drown out the ringing that seems louder when everything else is quiet, and especially if I lay with that ear facing the pillow.

The white noise gives me something else to focus on besides the ringing and all the day's thoughts that don't want to shut down.