This Android application is completely free and open source, 
released under the GPL V3 license (See http://www.gnu.org/licenses).

To install, search for binaural beats therapy in the market or click on this link directly from your phone:
market://search?q=pname:com.ihunda.android.binauralbeat

Documentation and more details in the WIKI:
https://github.com/GiorgioRegni/Binaural-Beats/wiki

Visit the forum to get help as well as participate in the app development:
http://www.binaural-beats.ihunda.com/forum

Giorgio
@GiorgioRegni on twitter