by Gareth J Barnard.
Dear Mary,
A quick Google (and from having tried myself with IIS once) gives:
http://www.simongibson.com/intranet/php2003/
http://php.net/manual/en/install.windows.iis6.php
http://www.microsoft.com/web/platform/phponwindows.aspx
http://www.microsoft.com/web/gallery/moodle.aspx/
Even though some are older PHP, the configuration though IIS should be the same. The last being I suspect a good way of seeing what is the ideal environment.
Alternatively, you can run Apache and IIS at the same time as long as they are on different ports (sockets). Then you can with the correct DNS server configuration have www.abc.ac.uk go to say 192.168.1.1:80 and moodle.abc.ac.uk to 192.168.1.1:8080 as an example.
Cheers,
Gareth