If you're using Win2k Professional on both systems, you'll have to set up DHCP. Your computer will be assigned an IP address in the 192.168.0.x range, and will forward all packets destined for any other network through your partner's computer. However, you will not go through his computer to access other devices on your LAN that have an IP address in the same range.
Windows 2000 Server includes much more flexible routing capabilities. Also, there are many non-Microsoft hardware and software solutions available that provide NAT services.
This was first published in February 2002