The O'Reilly site, OnLamp has a neat little article that has an introduction to functions and some examples of usage. They also show how you can use these self-made functions throughout your code (even how to give them default values). Thanks to EvilWalrus for that link.
For those that haven't seen it yet, PHP.net has put up a new Calendar that keeps track of any of the upcoming PHP events. This is a great idea - I just wonder why it wasn't up sooner (heh). You can add events (I assume for approval) and view events for months to come.
And, last but not least, for those out there that just have to have their fix - the latest Zend Weekly Summary is in place. There are mainly some small fixes, with an interesting note that, yes, the PHP packages work on Windows XP (shudder) and that they work best right out of the box.