Remit
Remit is currently a bare-bones Ruby interface to the Amazon Flexible Payments Services (FPS). We’re still working out a few kinks before making our first public release. Eventually it will provide a rich API for interacting with FPS. We’re taking a different kind of approach to this project by starting out with the necessities, and then making the interface nicer as we discover where it needs the most attention.
See the RubyForge project or the Google group for more details.