Sadly, mozex isn't working anymore for Firefox 3.0. I was looking at hacking it to make it work, and make it work better with Emacs, but then I found:
about:config view_source.editor.path
Unfortunately, this didn't seem to work with my emacsclient setup, until I found:
Emacs as default View Page Source / Greasemonkey editor in Firefox on Windows
So, I just editted my "firefox-emacsclient" script to look like this:
#!/bin/sh
/usr/sness/emacs/bin/emacsclient -c -n -s sness $1
and I can get beautiful source code viewed in my favorite editor.
