I recently had the need to get PHP (which I've never used prior to this) and MySQL up and running on IIS on my home machine which is running Vista Ultimate Edition. I was able to get PHP 5.2.3 up and running by follwing the directions here on BillS' IIS Blog. I was able to install MySQL which is a bit tricky to find on the MySQL website if you are looking for the free version here is a link to it.

I was able to install MySQL just by using the Install that came with it, no tricks or problems. Then I installed SQL Manager 2007 Lite For MySQL to be able to manage the databases. I was able to install and connect without any problems.

I then needed to get PHP and MySQL working together. I went into the PHP.INI file in c:\Windows and uncommeted the line for the driver php_mysql.dll and updated the line extension_dir to set it to "c:\php\ext". I then created a simple PHP page calling PHP_Info and saw that it was loading the correct INI file in C:\Windows, but was not seeing my updates. It was not looking for the extensions in the correct directory or seeing that I was trying to load the extension php_mysql.dll.

After much distress I found the trick. I had to recycle the DefaultAppPool in IIS to get it to read the PHP.INI file again. Restarting the server dind't even seem to do the trick. So if you have this problem try -> start - run - inetmgr - "Application Pools" - DefaultAppPool - Recycle.

I hope this helps soemone out there...