Please go to SBaGen -- Binaural Beat Brain Wave Experimenter's Lab for complete information and FAQ. Here is the direct link download for sbagen v.1.4.4

Sbagen generates pink noise and binaural tones through soundcard in real-time according to a 24-hour programmed sequence read from a file. It can also be used to play a sequence on demand, rather than according to the clock. MP3 or OGG soundtracks may also be mixed in instead of pink noise.

The basic idea of binaural beats is that by applying slightly different frequency sine waves to the two ears, a beating affect is created in the brain itself, due to the internal wiring of the brain. If, in the presence of these tones, you relax and let your mind go, your mind will naturally synchronize with the beat frequency. In this way it is possible to accurately lead the brain to various states, according to the frequencies that you apply.

It is also possible to play several different tones together, giving several different beat frequencies, and programming quite a complex brain-state based on several frequencies (in several different bands). These complex mixtures of frequencies are the basis of the Hemi-Sync(TM) process from the Monroe Institute, based on Robert Monroe's experiments with out-of-body experiences and so on.

Taking an alternative approach, CenterPointe use single tones, but vary the carrier frequencies to achieve a kind of emotional cleansing effect, which is also an extremely valuable and interesting technique. There may well be other useful binaural beat based techniques yet to be discovered. For an overview of the theory of binaural beats and how they affect the mind, take a look at the Monroe Institute site.