|SBaGen: binaural beats for brainwave entrainment: http://uazu.net/SB|
My SBaGen tool is a freeware binaural beat generator, designed specifically for use in entraining brainwaves, that runs on Linux, Windows and Mac OS X. It is especially suited for long entrainment sessions as it can be driven from clock-time, making it ideal for setting up overnight sequences, even including a wake-up sequence at the end to (hopefully) give you a good start to the day.
Both CenterPointe and the Monroe Institute have done a great deal of research into binaural beats, and their sites are worth visiting for more information. CenterPointe concentrates on using binaurals for personal growth and improving well-being and holistic functioning, whereas the Monroe Institute appears to be more interested in research into unusual states of consciousness (out-of-body experiences and so on). For those who prefer to pay for a programme that gives support, I recommend looking at the CenterPointe site (and see my disclaimer).
For more details on all of this, see my main SBaGen page here.