Rated 5 out of 5 stars

for FF6 modify urlbarExt.xpi:
Right click "Add to Firefox" save as urlbarext.zip. Open file, edit.install.rdf, find em:maxVersion>5.0 and change to em:maxVersion>6.0, save install rdf, rename urlbarext.zip urlbarext.xpi and drag into ff6 it then insatlls asks you to restart FF..

This review is for a previous version of the add-on (1.8).  This user has other reviews of this add-on.