Duvet-dayz has an outstanding tip sheet on firebug (via dzone) with keyboard shortcuts and mouse actions arranged by Windows, Linux and Apple operating systems.

If you use the firebug addon a lot, Digital Media Minute has done articles before on firebug tips as well a very popular post on debugging JavaScript with firebug for Firefox.

Veera Sundar has a nice list of five ways that you can use firebug to edit HTML and CSS. It is amazing how easy firebug makes it to visually modify a page layout…
If you’d like to go deeper, Digital Media Minute as a popular tutorial on debugging Javascript with Firebug.

In case you haven’t heard, yesterday Firebug 1.5.0 was released by Joe Hewitt, Rob Campbell and the rest of the gang at the FirebugWorkingGroup. New for this release, which is apparently a big one, is an enhanced Inspector, improved HTML editing and a lot more. Digital Media Minute did a very popular Firebug tutorial screencast a while back, by the way.