The Mac version is still only promised to be coming soon, but Amazon has today delivered a fairly big update to its Cloud Player for PC application. It now boasts an integrated MP3 store, which will let you browse and purchase music without having to visit Amazon's website. Naturally, all purchases made through the app will then be accessible from any other capable device, and you'll see Amazon's usual recommendations for new music based on your purchases. Beyond that, though, the application itself appears to remain mostly unchanged.