I finally got our extension working with Firefox 3. And added support for all of our voices, the ability for the extension to save your preferred words per minute and volume level. I will work on it saving your preferred voice soon.
You can download it from this page:
And if you can, write about it on https://addons.mozilla.org/en-US/firefox/search?q=SpokenText&cat=all
So that we can get it added to the public FireFox addons site.