1. Install GreaseMonkey. You can find it here:

https://addons.mozilla.org/fr/firefox/addon/748

If you have never installed a Firefox extension before, the browser will warn you that the site addons.mozilla.org is not in the allowed list. Just change the preferences to allow add-ons installations from addons.mozilla.org.

2. Install the script. You can find it here:

http://userscripts.org/scripts/show/25396

Then you just have to browse to one of the Monsters applications and the script will begin to work. For example go to this page:

http://apps.facebook.com/slayers/

PS: I also sent you the answer by mail.