iptables -t nat -A PREROUTING -i $yourethernetcard -p tcp --dport 80 -j REDIRECT --to-port 3128 -d ! mysite.org or give the ip address of the site.
This sounds to me like transparent proxying, ain't it?
iptables -t nat -A PREROUTING -i $yourethernetcard -p tcp --dport 80 -j REDIRECT --to-port 3128 -d ! mysite.org or give the ip address of the site.