Source Magazine has posted a Internet Connection Sharing guide
So you’re a gamer on a budget seeking a way to connect all your home computers to the Internet via one connection. How, you ask, can this be done? Well, numerous ways exist for you to do this, ranging from a high-end Cisco router solution to what I call the Brooklyn method (this is where you yell downstairs to your sibling "Hey—I’m on the Internet…don’t pick up the telephone!").Read more
In Windows 2000, there is a built-in method for connecting to the Internet and creating a "share point," so all the other computers on your home network can share this one connection. It’s called, not surprisingly, Internet Connection Sharing or ICS. ICS is available in both Windows 2000 Server and Professional operating system versions. The key point is that multiple people can be on the Internet at the same time.