Python library for Amazon MWS
didn't find one so developed my own basic version: http://code.google.com/p/amazon-mws-python/
Try boto... I don't think they have MWS yet, but they might add it soon.
UPDATE: Sorry, I mean try making a request to the boto team. Boto seems the be the fullest python library for AWS right now, so it makes sense for them to add it.
More up-to-date and feature complete version is here. As I understand it's based on Richard's original version.