|Configure the DHCP service on the 2003 Server.|
Connect the server and all client PC's to the same switch.
Ensure all clients are set to DHCP and allow them to get their TCP/IP settings from the server's DHCP service. If you've configure DHCP correctly and the server's TCP/IP settings are also configured correctly (ie: for the same subnet as DHCP) then all should communicate with each other properly.
It matters not how straight the gate,
How charged with punishments the scroll,
I am the master of my fate;
I am the captain of my soul.