Keep in mind that the IIS server in Win2K is very limited in terms of the numbers of connections it can accept. The maximum is 10 connections. That is usually plenty for a testing environment, but is often insufficient for a site on the net.
To view the PC from the net you need to have a static IP for that machine. Then you will have to make that machine's port 80 open to accept connections from the net.
There are all sorts of way that you can also achieve this with dynamic IP addresses and your router's DMZ, but you didn't specify your setup.
Thanks for the replies. After much Googling I did finally discover how to do it (most of the time was taken up by working out what questions to ask!). I set up a static IP address on the pc hosting the site and used port forwarding on my Linksys router.
I'm using the setup to host a website while I'm developing it and to allow the client to view it over the internet when I need his input. I really need to go into the security issues I guess although I'm only allowing external access for short periods while the client's actually looking at it.
Any advice on security issues would be welcome. The host pc has the free version of Zone Alarm running. I'm also using the IIS Lockdown Tool and the MS Baseline Security Analyser, but haven't really got to grips with them yet.
The IIS Lockdown Tool and the MS Baseline Security Analyser are good first steps. I think those are the basic minimum you need to take care of before opening your server to the net.
Another precaution you might want to take is setting a password on the entire site. Use the Windows authentication for login. This prevents casual browsers and SE bots from finding and indexing the site. Just give the account minimal permissions on the web directory and you should be fine.