During the last years I found PHP to be an amazing easy to learn and easy to use programming language. It has become my preferred language for most of the web applications I develop. One of its main advantage is the amazing collection of various open source web applications that were developed in PHP. Joomla, Drupal, WordPress, Moodle, SugarCRM are just few samples.
Working with .NET software developers I find that many of them are not aware of the possibility to have PHP web applications up and running on their IIS server. This available integration between the PHP platform and the IIS server allows us to enjoy those open source web applications on the IIS server as well.
The php.iis.net web site is a great resource for getting more infromation about the possibilities for having PHP web applications deployed on a .NET environment.