What is different from Firefox 3.6 tab previews? Rated 4 out of 5 stars
It seems that it is already included into Fire-fox 3.6. It's not needed any-more!
P.S. The only difference seems to be absence of browser.ctrlTab.mostRecentlyUsed in Firefox 3.6.
P.P.S. To enable it in Firefox 3.6 set browser.ctrlTab.previews to true.