Rated 5 out of 5 stars

You can install this on the latest release candidate for Firefox 3. I haven't tested stability, but I did get it installed. Right-click on the link and save the .xpi file to your computer. Rename it to .zip. Unzip. Open install.rdf with notepad. Find the Firefox section and change the maxVersion to something greater than 3.0 (I chose 3.5.0). Save install.rdf. Zip the entire directory back up. Rename back to .xpi. Drag the .xpi into a Firefox window. Voila - it works.

This review is for a previous version of the add-on (