virtual network adapter?

I'm wondering if anybody here has any experiance with these... I want to get a proper VPN running on server 2k3 but don't want to waste the resources on an extra card on the machine...

When I have installed the various cisco vpn clients they basically just run a script that installs an .inf file, (which then installs the .sys file) There isn't much to it from that perspective.

Are you trying to make a vpn tunnel, for the whole network, or just the server box?

I'm making a VPN server.