Hate Seeing Ads on Sites? Get Adblock Plus

https://addons.mozilla.org/en-US/firefox/addon/1865 - Adblock Plus is a Firefox add-on that claims to hide 99% of advertisements on websites. When you run this extension, you can right-click on a banner ad, image, ad module, etc., and opt for it to be blocked. When you do this, the add won't appear ever again. Better yet, Adblock Plus lets you subscribe to ad filters, which are databases that contain information on ad modules, so you don't even have to block the ads yourself. Everything will be done for you.

However, this extension has yet to find support in Firefox 3 Beta, so it will only work on version 2 at the moment.