[Tabby is now obsolete. For Firefox 4+ users, checkout Tabby 2 at https://addons.mozilla.org/en-US/firefox/addon/tabby2/.]
Tabby is a simple Firefox extension that helps you search for and quickly switch to a tab.
1. Press Ctrl-' (Control and single-quote key) to toggle the visibility of the Tabby bar, which resides at the bottom of the window.
2. Type one or more keywords in the Tabby bar, and a list will pop up and suggest you possible tabs.
3. Choose the right entry and there you go.
Please go to http://code.google.com/p/tabby-firefox/issues/list for feature requests and bug reports. You can also simply leave a comment below to let me know what you think.