This is a nice extension that allows google map to take over the whole browser viewing area.
This extension is now only compatible with firefox 3 beta 5, nightly users might need to wait a bit. (google maps actually detect "firefox/###" in the UA, lol, so if you want, you can goto about:config and modify the UA yourself).
I found this one particularly useful for EEEPC (LOL)'s tiny screen. Plus Firefox 3 will auto-hide ALL the menu/toolbars when in "full screen" mode (win/lin only, mac version of full screen is still under review).
To install, goto https://addons.mozilla.org/en-US/firefox/addon/4026
This extension is now only compatible with firefox 3 beta 5, nightly users might need to wait a bit. (google maps actually detect "firefox/###" in the UA, lol, so if you want, you can goto about:config and modify the UA yourself).