Head on over to the firefox tabsearch project page and download it.
Download: tabsearch-20080430.xpi
Additionally, I've noticed that Firefox 3.0b5 doesn't seem to render this site correctly. Seems like it's ignoring my CSS of "pre { overflow: auto; }" which makes pre tags scroll if they become too wide. I'm willing to accept that I may be doing something incorrect (that has historically worked fine) - I'd much rather have the site render as intended. I'll look into it later.