Welcome to WebmasterWorld mroashan! I just set up a similar device to isolate my own network. The RT314 has NAT (Network Address Translation) addressing capability so there is little you will need to do. Netgear's explaination of NAT is at [netgear.com...] and it's pretty simple.
First, insert the settings your ISP requires when connecting to the Internet into the router. If you use a dial up or have a permanent IP address, tell the router, exactly as you needed to tell your local machine, pre-router. It becomes your computer as far as the ISP is concerned.
Next, set each machine on your local network to use DHCP (Dynamic Host Control Protocol), not a fixed IP addresses. This means that each time a networked machine connects to the network, the router can assign it a unique IP. On my machines (Win2K) this is controlled under >Network and DialUp Connections>Local Area Connections>Properties>TCP/IP>Properties. Select "Obtain IP address automatically" and "Obtain DNS server address automatically." How you change these settings will be different (but similar) on other Win versions.
If this is a new network, you will need to add the appropriate "shares" to each machine on the network so they can access each other's data. Also, you won't need to set up Internet connection sharing on networked machines, the router will handle that for you.