Virtual Private Network on OS9

I have a local area network of 2 iMacs, a G4 and an iBook. They're connected utilizing a Linksys WiFi router. I have a high speed cable connection to the Internet via DHCP.

Here's my question... How do I log into the LAN from a remote location? I have an employee who wants to work at home and needs to be able access files on the network.

Thanks