This application, in brief, covers 30 binaural wave tones ranging from meditative to lucid dreaming. You have volume control, time setting, and an option to either use the in-built tunes to accompany the binaural wave, or select your own personal tune from your music collection.
Personally, I use one of Brain Wave's in-built tunes turned down to a minimum volume, and have the binaural turned up to full max, which is still reasonably quiet (my wife sleeps happily through it without complaint).
In my own use I have found getting to sleep much faster and my dreaming has shot through the roof - which I personally enjoy, but then I either use the Lucid dreaming setting or the standard Dream setting, but I have used the Power Nap setting on several occasions when feeling the need to rest during an afternoon off work.
I've also discovered an online site that allows you to customise your own settings whilst at the pc, so you can 'tune in' your brain pattern to your desired purpose; it's called 'The Ultimate Binaural Beat Machine' - I'll be giving it a go later today after work.
Hope these two selections can help those amongst you for whom sleep evades or just struggling with concentrating whilst at the pc ;)