Firefox does not support any add-on of this nature. However, I just did a quick Google search, which you can also do, and selected the first two from the search results: http://www.totalrecorder.com/downloads.htm http://download.cnet.com/Free-Sound-Recorder/3000-2170_4-10698910.html I have no knowledge of either software. I do not know whether they are legal or not and Firefox does not guarantee either or recommend them above or ahead of any others. They are just an example of what you can find by doing a search. The search terms I used were: Free download Add-on record sound through sound card.