On the phpaddiction website, there's a quick new tutorial showing how to use the YAML technology to make a configuration for your application.

I have always disliked creating configuration data by reading from various formats into global arrays, so I needed to build or borrow a configuration class for my own projects that I could standardize on.

He discusses the base he worked from - a class based on the Zend_Config package in the Zend Framework, using his own sort of caching scheme. He's also included the code to see it in action (including the code download).