You can find the home page at http://firevox.clcworld.net/. Firevox, unlike Fangs, is a real screen reader. It also supports the accessibility keyboard shortcuts. Firevox is intended for users who actually need a screen reader to read the contents of an HTML document. In other words, it is a good reproduction of how a visually impaired user listens to an HTML document.
To install Firevox, however, you really need to read and follow the instructions at the homepage of Firevox.
The value of Firefox in addition to Fangs is somewhat marginal for web designers or developers who are sighted. Nonetheless, sometimes it is good to be reminded of how users who are not sighted perceive an HTML document. Furthermore, it is an excellent free resource for those who need real accessibility.