Might be cool to write a DAAP client that uses this so you get your Google Music inside of iTunes as a shared library. If I wasn't so loaded with stuff right now I might start a project. Oh, heck maybe I'll do it anyway.
On similar lines, I wrote an unofficial API for Amazon's CloudPlayer: <a href="https://github.com/mwylde/cloud_player" rel="nofollow">https://github.com/mwylde/cloud_player</a>.