From their site: Songza exposes some of its functionality via an API. You can build tools that talk to Songza. Use methods to return the 10 most played songs and featured songs, the last 10 songs that a user has added to their playlist, and the user's playlist.
Click the "Track this API" button on any profile page and never miss an API update, new app, or breaking news for that API again.
There are no source code libraries or how-to links for Songza. If you know one why not add it?
checkout this one