Very good and intelligent port of Squid and Dansguardian to Mac OS X without sacrificing 3rd-party compaitibility. Basically this is a cute GUI installer for the Squid proxy server and Dansguardian. It even works well in Panther.

All you need to do to have the filtering working is to install it, configure your proxy settings (System Preferences / Network / Proxies) to use 127.0.0.1 as your web proxy on Port 8080.

Want to tinker with the filtering? Go into the terminal and cd to /usr/local/etc/dansguardian and pico any of the text files in the directory. Most configuration is in dansguardian.conf, but some other handy files include the self-explanatory bannedsitelist, bannedurllist, exceptionphraselist, exceptionurllist.