If you are a web developer and have not download Firebug just go get it.  You can click here or type http://getfirebug.com in your browser address bar.  It’s an indispensable tool when developing and debugging you web applications.  From the Firebug web site; “Firebug integrates with Firefox to put a wealth of web development tools at your fingertips while you browse. You can edit, debug, and monitor CSS, HTML, and JavaScript live in any web page.”

Currently it runs as a Firefox extension but there is Firebug Lite which you insert into your pages to simulate some of Firebugs features.

Phil