Like the Mozilla DOM Inspector?

Linked from the wdf-dom mailing list you download and install a very good DOM viewer for IE from http://www.cheztabor.com/IEDocMon/ and if you’re not already using the appropriate webdev bookmarklets (if not, why not?), you can grab Source Tree which will show you the CSS and JS of a page, and all these from an explorer bar!

Excellent stuff!