Works with Firefox 12! Rated 5 out of 5 stars

I came across a working version of Ubiquity for FF12 here: https://addons.mozilla.org/en-US/firefox/addon/mozilla-labs-ubiquity/versions/?page=1#version-0.6.2pre This site has links to the ubiquity xpi for various version of Firefox. For FF12 you'll want to try version-0.6.2pre. So far seem to work great!

This review is for a previous version of the add-on (0.6).