MidiDroide

"MidiDroide" allows us to use the devices as "Wi-Fi Midi Controllers." The application communicates with the PC (via Wi-Fi) and the data are interpreted by "MidiServer", this program is done in Java and is responsible for sending Midi devices we have in our system (Window / Mac). "MidiServer" is multi-client allowing you to connect all the "MidiDroides" we want!
Download MidiServer:
http://midiquet.wordpress.com/2012/04/17/mididroide-android-midi-wi-fi/