Yes! we've been asked to add Firefox functionality hundred times and we finally did it.
Version 1.0.0.8 works on Mozilla Firefox same way as on Internet Explorer. When you click the Clip Extractor toolbar button, the Clip Extractor window pops up with the URL of the video automatically pasted into the video link bar. No need to copy and paste anything!


Please note that the automatic update will not switch on the Mozilla Firefox support. In order to place the Clip Extractor button on the Firefox toolbar you need to download the complete installation package and either install it over the previous version or as clean installation.
You can download version 1.0.0.8 from here: http://www.youtubeclipextractor.com/download.aspx?version=basic

Please see this tutorial to make the Clip Extractor button appear on the Firefox toolbar.