As first reported by ZDNet Australia  earlier this week, the toolbar adds spell-checking and language translation features to Firefox, as well as the ability to use a single click to complete online Web forms such as shopping checkout details, and easy access to online data like geographical maps of addresses or publication details of books.
Firefox already has the Google direct search function (also included in the toolbar).
While the toolbar has been available for Internet Explorer for more than four years, Firefox users have thus far had to content themselves with the GoogleBar, an open-source alternative to Google's toolbar which mimics much of its functionality.
The two other extensions released by Google provide the ability -- only in the US -- to send short text messages of Web page content direct to a mobile phone, and to have search terms automatically completed as they are typed into Firefox's in-built search box.
All three extensions are available in 10 languages for the Mac, Windows and Linux versions of Firefox.
On Google's official blog, the team working on the Firefox toolbar gave credit to the Mozilla Foundation "for making it so easy for us to look good".
Google competitor Yahoo released a Firefox version of its own toolbar in February.