Sorry, silly me, you said win2003. It will be easier not to use NAT (which will just giove you a whole new layer of problems.
If yo uset up a new VMWare network, you can bridge it to the wireless NIC in the VMWare Host Virtual Network Mapping screen. Your VM should then pick up an address through DHCP if you want it to, or configure by hand if it won't.
You need windoze to be able to pick up and use the wireless card first of course. Can you run the host machine over WiFi?