Need to assign second address to teh same NIC in Windows 2003 Server

I need to have both external and local IPs assigned to one NIC in Windows 2003 Server .... I know how to do it it Linux and do it all the time, but Windows remains a mystery to me.  here's what I need to do:

assign IP 66.162.xxx.xxx to my NIC (I already have that done)

also, assign a local address 192.168.100.55 to the same NIC ....is that possible in Windows?  Or do I have to add a second NIC?

All advise greatly appreciated ....  and remember, I'm Linxu smart and Windows stupid ... gentle, step-by-step instructions greatly appreciated.

thanks.

Kenn