FF 3.0 workaround Rated 5 out of 5 stars
This Signature app is awesome, thanks for creating it.
***Firefox 3.0 Workaround***
To get this to work in FF 3.0 and above search for the Add-on "nightly tester tools" and install it. Select "override all compatibility" in the Add-on window of FF. Then download an older version of Signature from the "all versions" link. Enjoy!