From Offensive-security.com

Setting up TOR, Privoxy and Firefox

bt ~ # privoxy /etc/privoxy/config
Feb 26 16:42:04 Privoxy(-1210161472) Info: loading configuration file '/etc/privoxy/config':
bt ~ # tor
Feb 26 16:42:11.806 [notice] Tor v0.1.1.26. This is experimental software. Do not rely on it for strong anonymity.
Feb 26 16:42:11.808 [notice] Configuration file "/usr/local/etc/tor/torrc" not present, using reasonable defaults.
Feb 26 16:42:11.808 [notice] Initialized libevent version 1.1b using method poll. Good.
...
Feb 26 16:42:20.754 [notice] Tor has successfully opened a circuit. Looks like client functionality is working.

Then click on the bottom right corner of the firefox browser - where is says "Tor Disabled" in red. :)

muts

NOTE: This enables Tor for Firefox. You will have to manually configure other applications (GAIM, etc.) if you wish to route them through Tor. Go here to learn how to configure other applications. -theprez98