Rated 5 out of 5 stars

by Daniel Haertle on Dec. 10, 2009 · permalink

While unfortunately unmantained since many years, it also works in Thunderbird 3.

For how to make it work, see
http://www.techsupportalert.com/content/how-update-firefox-thunderbird-addons-new-release.htm
or download the compiled addon at
http://haertle.ch/programs/signature/signature-0.4.20091210.xpi