A couple of items that may be of interest.

Firstly for Firefox users.
There is currently a third-party Googlebar available, but Google will shortly be releasing their own Google Toolbar for Firefox containing most of the features of the IE toolbar.

Secondly for Mozilla Suite users.
The Mozilla Foundation announced several months ago that it was discontinuing development of the Mozilla Suite. An independent group has taken over development of the suite and future releases will be known as SeaMonkey