Packt Publishing has posted a new article from Jani Hartikainen about the "magic methods" that PHP comes with - methods, properties and constants really.
Magic methods, which are class methods with specific names, are used to perform various specialized tasks. They are grouped into two: overloading methods and non-overloading methods. [...] Magic functions, which are similar to magic methods, but are just plain functions outside any class. [...] Magic constants, which are similar to constants in notation, but act more like "dynamic" constants. We'll also look at some practical examples of using some of these, and lastly we'll check out what new features PHP 5.3 is going to add.
He looks at the various functions/methods and constants (like __clone, __toString), some of the overloading methods like __call, and magic constants like __FILE__ and __CLASS__. He wraps it up by briefly discussing what PHP 5.3 adds in - a few new magic methods and constants (but no functions).