Adding another IP to network card

i realise this is a bit OT but I know there are network guys on this list and I'm hoping for a quick solution. I need to temporarily host another web site on my server. I don't want to chage any DNS registrations as it's only for one day. How do I bind/associate more than one ip address with my NIC. I tried `ipconfig add xxx.xxx.xxx.xxx` and it seemed to work but it only works for local subnet conmnections. What am I missing? -- Simon Oliver