>How can I resirect outside requests to another IP in my LAN?

/rant on
Why would you use a computer with Windows 2003 (USD $1,000+) when a simple router (D-Link DI-604 USD $50) can do the trick?
/rant off

Check out this webpage: http://www.microsoft.com/technet/community/columns/cableguy/cg0503.mspx it has info on how to set up NAT within Windows 2003.

HTTP uses port 80.

Hope this helps.