BloGTK is a weblog posting client written in Python for any platform that 
supports Python and the GTK widget set. BloGTK allows you to connect to your 
weblog with XML-RPC and create new posts.

Supported weblogs:
MovableType versions 2.5 or later.
Blogger
WordPress 1.5 or later or WordPress.com
Windows Live Spaces
Expression Engine (but autoconfiguration does not work)
Any blog that uses the MetaWeblog API.

WWW: http://blogtk.jayreding.com/