Our project is available as an Android package. It should run on any version since Android 2.3.3 (Gingerbread).
To run the prototype, install the Android SDK and use adb to install the package by following these instructions. (It seems like there ought to be an easier way to do this, but we haven't found one.) Right. Apparently you can just download the file from your phone and everything just works. This should add VoiceComposer to your device's applications, after which you can start it like any other app. We haven't done any cross-device testing, so if it crashes on startup or something, let us know and we'll try to fix it.
Each song in the list on the main screen has four buttons on it; only the rightmost is functional. The audio output is a bit unreliable (we'll look into fixing that for the next version). Recording is fake; the final app will use the microphone, but this version simply goes through a fixed sequence of notes.