This new post on the Symfony blog today looks at using the framework's built-in support for the YAML format. They include a few examples of the code to make the files and how to use them.
Here is a short tutorial about my discovery of the new YAML parsing library that comes with symfony 1.1. As you may know, YAML files are a place symfony developers spend time writing configuration, it is very important they have a good tool to manipulate data and debug files.
They include code showing how to pull in a sample file, access the properties inside of it and how to take a multi-dimensional PHP array and push it back out (automagically) into a new YAML formatted file.