This is a really good Add-on from FireFox which enhances the Full Screen mode into a really full screen mode, hiding the remaining toolbars and statusbar and making them visible again when the mouse pointer hits an edge of the screen.

To install the add-on, visit FireFox Add-ons site. Once there click the Install button and FireFox will walk you through the installation process. Once this is installed you will need to restart FireFox. Then, open the Ads-ons manager by going to Tools->Add-ons and select Fullerscreen. You can tweak the Fullerscreen’s behavoiur from the preference dialog.

Once you have set your preferences, close the Add-ons manager, go to a web site that you want to see full screen and press F11 or click on the Fullerscreen icon on the status bar.

This is a cross-patform compatible extension and works well on Windows and Linux, should work well with Mac i guess.