Subnetting Class-C IP addresses in a home network
Network security has become a large concern for even the avid home internet user. With more and more wireless routers and broadband connections out there connecting to the internet there is one thing that you can do to help isolate your private computers from the internet and still allow them to access the web. All you need are two standard home-use routers. I prefer the Linksys ones but any that are configurable for NAT will do.

Subnetting :)

Take a look at this network page from TCPIPPrimer.com to help you split up your current Class C network into 4 separate networks (Daryl says 2 but with this configuration, you can do 4), each isolated from each other yet all accessible to the internet.

http://www.tcpipprimer.com/routing.cfm