] This HOWTO explains how to browse the web anonymously by
] using Tor (http://tor.eff.org/) (TheOnionRouter) and
] Privoxy (http://www.privoxy.org/)

This howto explains how to use Tor and privoxy together to get fairly strong anonymity protection. Combined with switchproxy in firefox this could be quite useful. Thing is you'd think that a lot of the features of privoxy could be implemented as firefox plugins rather then running this dual proxy setup, but thats just the engineer in me bitching about efficiency. I think that this setup would likely work reasonably well, given the performance impact of onion routing.

HOWTO Anonymity with Tor and Privoxy - Gentoo Linux Wiki