VPN’s in Win 2K Small Business Server

I am a college student who does mostly hardware consulting work on the side. I was recently asked if it was possible for a computer with an external ip address (running Windows XP Pro)to access a Win 2K Small Business Server (and network)using a VPN. There is a catch. The server is connected to a Linksys router along with the clients sharing one external ip address. As an end result, the user wants the remote computer to act if it was on the job location. (Access all hd’s, control using netmeeting, etc.) Are there built-in functions in the remote computer, server, and the router to do this?