The Reveal Extension for Firefox is very cool. It uses some new Firefox 1.5 features to create nifty thumbnails of each open tab, and it can also render the “session history” of each tab as a series of thumbnails.
After you install Reveal and restart Firefox, a little popup will offer you a guided tour. If you choose not to take the tour, you can activate it at a later time using the “Tour Reveal” option in Firefox’s Help menu.
Reveal is activated using either F2 or the Alt-backquote combination. Once activated, you can see all of the tabs, select one and hit Insert to see the session history for the tab, drag the images to rearrange the tabs, and more.
Reveal will also drop down a thumbnail when you hover your mouse over the Forward and Back buttons in the navigation bar.
There are lots more options, and this extension is definitely a keeper!