Have one web server use port 80, and the other use port 88 (or whatever), allow access thru the DSL router for both ports on either machine. You should be able to go http://you.dns2go.com:80/ for one and http://you.dns2go.com:88/ for the other - the ip address of the router gets accessed and forwards to the computer, and you'll only need DNS2GO on one of the computers.