Rated 4 out of 5 stars

http://rapidshare.com/files/215482745/signature-0.4.0.5.20070419-fx_tb.xpi

Just download the file and open it from file>open file... in firefox. It contains a patched version that should work for all firefox 3.* installations. Provided as is, with no warranties etc, etc. I figured I could make this easy for people who don't know how to / don't want to edit the xpi file.

This review is for a previous version of the add-on (0.4.0.5.20070419).