Dead now (like Google Music itself, RIP)
To use the API in your project, simply drop in the .h and .m files into your project and include them as you would any other class. Then, in the view you want to use it in, make that view a subclass of GoogleMusicViewController, and implement the methods as shown in the example.
Currently, all requests are synchronous, but given the general use-case for this sort of API, I think this makes the most ssense.