Yoga Sound is originally to help focus while doing Yoga, and has claims to also help people relax, deal with stress, and get to sleep. By developer George Talusan, the app is $0.99 in the iTunes App store. Talusan also has other, very similar looking apps for a range of prices, some of which are free off and on, and seem to be the same thing repackaged over and over again.
The app itself is a very simple media player with pre-loaded sound clips of ocean surfs, birds, waterfalls, rain and other such sounds. It will only play these clips and other sounds that can be purchased for $0.99 each.
What I found is that while I liked the free clips available, the player pauses if I move out of the app, or if the ipod goes into safe mode. Which is really annoying, and it doesn't look like there is an option menu to change it.
I think that what would be a better alternative to this app is to purchase music you find to be relaxing, add it to your regular player, such as itunes, and just have it on repeat.