I would just pick up a 4 port hub and then jack each machine into the hub
then out to the net....
Catnip is right:
When using a hub or switch (instead of a router) for that sort of configuration, you need to check with your Internet service provider first.
If the ISP only allocates 1 IP to your account, uses the MAC address of the connected computer as part of your account/connection validation, or uses any other methods which would disallow concurrent logons from multiple computers, a hub or switch won't do the trick. Many ISP do have limit like this, and the choices in that scenario are either to see if the ISP allows you to purchase additional IP addresses, or to use a router instead of a hub.
A) Broadband routers use NAT (Network Address Translation) to allow multiple computers to share a single connection (without your ISP knowing that you have more than one machine connected). Hubs cannot do this.
B) Broadband routers can be configured (via port-forwarding) to allow computers on the LAN (your internal network) to act as Web, FTP, game, etc. servers to the outside world, while still providing some measures of security for those machines. Hubs cannot do this either.