I recently use markdown to write my blog post in Emacs, and convert it to HTML with the official markdown.pl perl script, then paste it to blogger.
First, grab the markdown.pl from Markdown website and put that in one of your $PATH. I put it in $HOME/bin.
Then, start from scratch, type your post in using Markdown. When your're done, hit
Then copy the HTML out of the shell command output buffer. done.