CakePHP is an open-source framework for PHP intended to make developing, deploying and maintaining applications much easier. CakePHP offers many useful design patterns, such as the Model-View-Controller pattern, seen in other popular frameworks like Ruby On Rails. The CakePHP framework also provides a slew of valuable reusable libraries for dealing with common tasks. An example is "Inflector" (a routine that takes a string and handles pluralization).
They step you through the download, installation and configuration of the basic CakePHP setup. Included are definitions for some of the common parts of the framework like models, controllers, plugins and the vendors directories.