Disclaimer: I did a quick search and didn't find any threads that really addressed the new DRM-free amazon music store so I hope I'm not resurrecting an old argument.

Amazon allows access to its new music store through the free Amazon Associates Web Service (AWS).  I don't know anything about the architecture of Amarok but AWS has ruby bindings which makes it a great candidate for a plugin using Kross.  The API is easy to use and the most interesting things it includes are shopping cart and search support.  It also looks like customer review support exists.  It would be cool to have a large selection with such extra features exposed.  If this is a moral/political issue with the already supported Magnatunes the music it offers could be prioritized or something.

Information on AWS: http://www.amazon.com/E-Commerce-Servic ... e=12738641
Developer Resources: http://developer.amazonwebservices.com/ ... egoryID=59

I'd be happy to help, unfortunately I'm just getting into KDE and QT; coming from only MFC GUI development (which I despise and would hardly call a toolkit) it looks straightforward and clean.  If it's as easy as writing a new backend (don't know how you organized the Magnatunes thing) I'd gladly help with that.

The framework for generic music stores is pretty much implemented in Amarok 2 - you could check out the amarok mailing list archives http://mail.kde.org/pipermail/amarok/ or subscribe to the list to be kept up to date on what's happening, and find out how to contribute.