Firefox 3.x
Windows
Mac OS X
Linux
"Those of you accustomed to running IE have probably used the "new tab" button that is located on the browser's Tab Bar quite often. It is much easier to open a blank tab this way instead of utilizing a menu option or even a keyboard shortcut. New Tab Button on Tab Right is a Firefox add-on whose name is very self-explanatory. By installing this extension, you are given the same convenience that IE users have when it comes to opening a new tab in the form of a button on the browser's Tab Bar. The location of this button is configurable as well, although that particular feature appears to be somewhat buggy."
"Adds a new tab button like IE7."

