The totally awesome Firebug Extension for Firefox is approacing 1.0, and the screenshots on the homepage look awesome.
In his personal blog Joe suggests that he might want to start charging a small amount for Firebug. I think, given the inordinately useful nature of the application that it is entirely fair – especially as it would mean a dedicated tool-builder or two working on the project. Still, everybody likes free (as in beer), don’t they?