The International PHP Conference of 2002 was quite a success and many good presentations came out of it. They covered a wide range of topics, including "MySQL Performance Tuning", and "Caching Technology with PHP". One of the more "in depth" topics, though, was the presentation by Chuck Hagenbuch of Horde Consulting - Applied OO PHP: APIs, Design Patterns and Useful Objects.

The presentation was created to present an overview of Design Patterns and other solid OO design concepts, show how to implement those concepts and patterns in PHP, and then give a number of examples of those patterns in working, real-world applications.

They give some good examples (including some from Horde) on how to use these design ideas, and what "designing" your application is and isn't. They give three examples of application designs in PHP, including "Abstract Factory", "Singleton", and the "Observer" patterns.

Thanks to Ewald for the link...