You'll need a small hub or switch and NICs for each of the three PCs. You can use Internet Connection Sharing (ICS) to share your connection. Its included in Win98SE and up. The built-in help system in Windows has all the info you should need on it. If you have a broadband connection, Linksys, Netgear, etc. make "broadband routers" with a built in hub or switch. Those allow you to share the connection and get your PCs networked all in one shot.