Some adjustments regarding getting a Squid proxy going on Ubuntu...
Squid Wiki instructions on transparent proxying: I'm not using a MASQUARADE rule on my setup, but rather an SNAT rule...
iptables -t nat -A POSTROUTING -s (local subnet) -j SNAT --to (external IP)
* Ubuntu Karmic isn't using the newest Squid by far: it currently uses Squid 3.0.8, but you can install 3.0.19 just fine. I also updated iptables from 1.4.4 to 1.4.6
*Debian Sid SQUID3
*Debian Sid SQUID3-Common
*Debian Sid Squid-langpack
*Debian Sid iptables & ip6tables