Forget IIS. Use Apache with PHP. You'll save yourself a lot of trouble and headaches if you simply switch to Apache. The PHP support is much better with Apache and there are plenty of good hosting companies out there that support LAMP (Linux Apache mySQL PHP) platform. They are affordable as well.
Here's a general installation guide on how to setup Apache with PHP:
Apache/PHP Installation at KerryOnWorld
Note: The URL link above is subject to change
