IIS Aid

PHP is technically a platform independent language, however when developing PHP web applications you still need to be aware of the differences in the web server platform you are developing for, and also keep in consideration the possibility for migration between platforms into the future. I found this article some time ago which compares Apache and IIS PHP server array superglobal keys. While probably getting a bit old now, it is still a good example of the bigger picture you need to keep in mind when developing your PHP web application.