There's also Xdebug, which Derick Rethans develops and maintains. It's used for the debugging support in Komodo, for one.
One of the things I found at php|works is that the people who actually develop the language don't tend to have fanatical devotion to their language; instead, they look at other languages as tools, each of which might be more suited for a particular job than another, and each of which has something that they might learn from and adapt (or evolve) for their own language. Quite refreshing. I'm looking forward to YAPC 2005!
Oh, another item for the cheat sheet: the & sigil means very different things in Perl and in PHP. You know what it does in Perl, but in PHP the & means "pass this by reference". You can prepend it to a variable when you pass it into a function, or assign it to another variable, or you can prepend it to the variable name in a prototype so that you always get the reference to the object being passed in.