Greasemonkey is a great Firefox extention that you can read all about and install at Mozilla Add-ons. After instaling it, there are hundreds (Thousands? Probably not yet.) of scripts to install at Userscripts.org.
I have written two Greasemonkey Scripts for use at Rum and Monkey. They are as follows:
- Rum and Monkey Ad Removal - Inline text ads can't be blocked by Adblock, so they have to be removed in other ways.
- Grey Bit Remover - Removes the somewhat less than popular grey lines aborning the sides of the pages.