By default, Firefox 3 places the Home button on the Bookmarks Toolbar. If you don’t use the Bookmarks toolbar or if you just want the Home button to be back where it used to be, you can easily move it to the Navigation Toolbar by following these steps:
1. Open Mozilla Firefox 3. Your Home button will be located on the Bookmarks Toolbar.
2. Right-click the Navigation Toolbar and select Customize from the resulting menu.
3. With the Customize Toolbar window open, go to your Bookmark Toolbar and left-click and hold the Home button and drag it to the desired location on the Navigation Toolbar. Release the left-click.
4. Click the Done button in the Customize Toolbar window.
5. The Home button will now be located on your Navigation Toolbar.
Screencast: