After wasting a lot of time attempting to get Joomla 1.5 to work on Windows 2003 and IIS 6, I scrapped that idea and tried again on Windows 2008 / IIS 7. This was so much easier!

Here are the tutorials I used to load PHP and MySQL. Once they were installed and configured, I simply created a database (using the community version of SQLyog) and installed Joomla 1.5.

http://www.trainsignaltraining.com/iis-7-install-fastcgi-php

http://www.trainsignaltraining.com/install-mysql-on-iis7