Google Music is awesome, but I think we all can agree that its app kind of sucks.
Well, okay, maybe it doesn't suck, but there are tons of third-party music apps that are better; even the native HTC Music is pretty cool with Beats Audio. These alternatives bring so many features to the music listening experience that Google Music simply cannot. Unfortunately, most users (like me) are stuck using Google's simplistic app on their HTC EVO because that's where the majority of their music is stored.
Although this may be months away from completion and it may be shut down by Google at any time, a company intern named Simon Weber has been working on an unofficial API for Google Music. In plain English: this guy has made it possible to use Google Music without Google Music on your computer.
Weber is teaming up with CM9's Music app developer Andrew Neal to bring the API to Android. If everything goes well and Google doesn't step in and stop the project, this could mean that third-party app developers could grab the source code and add it to their apps.