For the purpose that brainwave described, it might be usefull to know that you don't actually have to find for the site you want, all you have to do is search for
cache:www.example.com

This trick is really useful, but it won't take long for the people who set up the firewall to figure it out (and disallow "http://www.google.com/search?q=cache:*" (they did this at my school))... just don't forget BabelFish and The Dialectizer and any other site which is capable of downloading off another site...(ie: a web based cgi proxy)

Also see: How to get around censorware and Another way to defeat URL filters