Firebug is a Firefox and Chrome add-on for web developer that allows developers to inspect, edit and debug CSS, HTML and Javacript on any live web page. It is extremely handy for seeing the computed styles for an element and determining in which stylesheet line a particular style attribute is being set. Changes can be made in real-time viewing the results on the page before making changes to server files.
This came in very handy in adapting the KWLUG theme to the Drupal 6.
Donations can be made via paypal from the Mozilla add-on page https://addons.mozilla.org/en-US/firefox/addon/firebug/.