Brandon Savage has a new post to his blog today looking at autoloading in your application and how the functionality the Standard PHP Library (SPL) provides can make life simpler.
If you've been in the business for any length of time you'd recognize this because almost every single PHP developer does it at one point or another. Until they learn about SPL's autoload functions, that is.
He talks about the spl_autoload_register function that allows you to define your own custom callback function (not just __autoload) to handle the inclusion of the needed files. He even gives examples of some more complex situations where autoloading like this could come in handy.