It is comparetively easy to share your residential Internet connection, generally there are three ways you can go. You should always check with your
ISP to make sure that this is legal to do under their agreement as well. The first, the easiest and recommended way of sharing your Internet connection is by using a
router. Check our "Hardware Reviews", we've reviewed numerous products in this category. Many routers have multiple
LAN ports, so sharing your connection is as simple as plugging every PC to the
router.
Another way of sharing your connection is by using one PC as a server (with two Network cards installed), and running software, such as
ICS, or Sygate, which routes traffic to other PCs on your local network. You still need a hub, or a switch if you have more than two PCs.
If you already have a
LAN setup with a hub/switch, you could also ask your
ISP to provide you with a second external
IP address, and you won't have to install any additional software/hardware. The only downside is that residential ISPs usually charge $5/$10 monthly for providing you with those additional IP addresses.