Extending Firebug, Hello World ! (Part 1)

Software is hard | Extending Firebug, Hello World! (Part I.)

http://veerasundar.com/blog/2009/12/developing-a-firefox-extension-the-complete-tutorial/

http://blog.mozilla.com/seth/2008/04/07/the-story-of-a-non-hacker-who-wrote-a-firefox-add-on/