Greasemonkey is one of the most popular Firefox browser extensions because it gives you so many tools to increase productivity and render websites in your browser. At the time of this writing there is currently not a Greasemonkey extension via the Firefox 3 addons manager or the Mozilla addons website.

All is not lost however:

You can get a working version from the developer’s site. The folks at Download Squad installed the greasemonkey-0.8.20080609.0.xpi into Firefox 3 RC2 on Mac OS 10.5, and their scripts worked like a charm.