Firebug is one of the reasons that I changed to Firefox (from Camino, a faster, less memory intensive browser). It is so handy for checking under the hood of websites and anyone who does anything with CSS should know how to use it!
I was trying to find a video tutorial to show people on the Thesis forums how to use Firebug. However, the ones I found were either too old (Firebug has come a long way in the last year or two), or they were a bit long and rambling.
So, I decided to make one myself. It’s 6.5 minutes (the others I found were double that!) and gives an overview of how to use Firebug, including installation. Feel free to ask questions about it in the comments below!
In you need a slightly sharper version, you can watch the quicktime video.