can this vpn setup be done?

hi i want to vpn into my home mac from my work pc running win 2000. work pc is behind a firewall + NAT but i think i've got the ports allowed to let vpn out (i can connect to other network with vpn from there). my home mac is running 10.3.3 and is running NAT through airport base station. can i use something like vapor on the mac to act as a server? what free solution would i use on the pc? thanks mark