“What is Firebug?” you may ask. Firebug is an excellent Firefox browser extension that is great for troubleshooting, editing, monitoring, and debugging. It is free and open source. It is one of my favorite web development tools.

Here is a list of useful Firebug resources and tutorials:

1. Get Firebug
2. Firebug Documentation
3. Overview of Firebug – a very good and detailed overview written by Michael Sync.
4. Better JavaScript debugging in 15 mins by Digital Media Minute.
5. Firebug Tips and Tricks by seifi.org
6. 10 Things you didn’t know about Firebug by Eric Wendelin
7. How to debug PHP with Firebug by Mathias Bank
8. A Firebug Tutorial by evotech.net
9. Web Development with Firebug by Joe Hewitt (video).
10. Intro to debugging AJAX Applications with Firebug (video)
11. Introduction to CSS editing using Firebug (video)
12. Debugging with Firebug by Joe Hewitt
13. Using Commandline API in Firebug by Michael Sync
14. Script Tab: JavaScript Tutorial by Michael Sync
15. Net, CSS, and DOM Tabs by Michael Sync (at the bottom of this article you will find an index of all the article that Michael has written about Firebug).
16. About Firebug by Aptana
17. Firebug Working Group
18. Firebug Development Blog
19. Firebug Discussion group
20. A place to report Firebug bugs
21. Firebug Internals
22. How to Speedup Firefox if you have Firebug