Flashblock is an extension for the Mozilla, Firefox, and Netscape browsers that takes a pessimistic approach to dealing with Macromedia Flash content on a webpage and blocks ALL Flash content from loading. It then leaves placeholders on the webpage that allow you to click to download and then view the Flash content.

Install Flashblock 1.5.13
for Firefox 1.5 to 3.7a

Netscape 9 and Flock Install Flashblock 1.3.16
for SeaMonkey, Firefox 1.0.x
and other browsers

FlashBlock Homepage : http://flashblock.mozdev.org/