PB is right, I use the Delta Sleep System 2.0 CD by Jeffrey Thompson.
But now I'm trying something else that seems to work too, if you can hook up a computer by your bed. It's a program called NeuroProgrammer, free full trial for 15 days. It comes with different "sessions" you can play, they make wierd repetitive sounds that are supposed to stimulate your brain to produce waves of a matching frequency. There are sessions for sleep, for study, creativity, addiction relief, etc etc. I think it works even better than the CD but I've only used it two nights. I am using speakers not headphones, and it's suppsed to be better with headphones.
Neuroprogrammer uses isochronic tones which are the best tone to use for brainwave entrainment, but not as popular as monaural beats and binarual beats because the latter two are easier to hide inside pseudo-music.
Binaural beats are the least effective, and easiest to hide in music. They require headphones because your brain builds the beat as the difference in frequency between input in each ear - and if one ear hears any of what the other ear is supposed to be hearing, the beat creation doesn't happen. The Jeffrey T. CDs use binaural beats.
Monaural beats are built outside the brain and fed to your ears via speakers or headphones, already at the frequency you want your brain to adopt. But sort of slurred together. Isochronic tones are very distinct, isolated tones which is why they're harder to hide in music and most effective. That is my dummy's understanding of it.
NP also lets you record your own affimations (I love salads, I will fall deeply asleep, I am a worthwhile person, etc) and scripts, and you can play them back with the sound sessions. I'm just starting to dig through the documentation. I think something's wrong with my sound card because I only get the beats from one speaker and static from the other