Setting up VPN

I am running Windows 2000 server. I want to set up a VPN. I have a router running DHCP that is my gateway to the internet. Can I set up a VPN through this router? I have 2 NICs in my server but it is the only Win2K server on the network. I alsohave a NT 4.0 file server. When I try to create the VPN no one on the network can connect to the server but the VPN seems to work. How can I give access to my users on the network and to the VPN? Thanks in advance for any help.

Will