CodeBurner for Dashboard is an easy-to-use widgetized version of the original CodeBurner for Firebug extension.
The CodeBurner for Dashboard widget has a standalone interface, and more dedicated search tools.
CodeBurner for Dashboard provides tools for accessing the information in different ways. There is a text-based search that matches element, attribute and property names as you type, and a DOM inspector for looking up objects that appear in the source code of any page.
There is also a CSS inspector for looking through the stylesheets associated with the DOM inspector's page, giving you instant information about properties, selectors and at-rules.