I’ve recently started playing with emacs (again). One feature that I just tried out is weblogger mode. It allows you to post entries to your blog directly from emacs using xmlrpc. Very simple setup. Since I’m using elpa, I can do a M-x package-list-packages, select weblogger to install and install it. Once installed you simply run M-x weblogger-setup-weblog, provide the credentials and are connect to your blog.
Check out the docs over at the Emacs Wiki
To be honest, the only reason I wrote the post was to test posting from emacs!