OT: How to add tab-closing X in Firefox, like Galeon?

[Kent West <westk@acu.edu>]

Galeon has an X on each tab; clicking on the X closes that tab. I really 
like this feature, but can't seem to figure out how to add it to 
Firefox. I had it added a few (pre-0.9) versions ago via an extension, 
but that extension no longer seems to be available.

Does anyone know how to add the closing X to Firefox's tabs?

Thanks!

--
Kent