a9 have just released a toolbar that works in Mozilla Firefox on Mac, Linux and windows.

This is the first official toolbar for Firefox by one of the top competing search engines (MSN, Yahoo, Ask Jeeves and Google only have toolbars for IE.)

It allows all the functionality of the IE version - recording of the browsing history, access to your bookmarks, the diary & lists features and access to more information about the site you're viewing.

Download it at http://toolbar.a9.com/

More info about a9:
Toolbar help
Why use a9.com?
Amazon A9 Search -Is It Really A9 Out of 10?
A9.com Promotion Push Starts
A9.com Launches With Major Updates (15 Sept)
A9, Amazon's Search Portal, Goes Live: Reverberations Felt in Valley (14 April)