There is a free beta of Zend Studio 3 available (
http://www.zend.com/). The new version supports PHP5 and (gasp) syntax error displaying, among other things. Hopefully this will end my seemingly never-ending quest to find a non-crappy PHP IDE. If there was something like IntelliJ IDEA for PHP, then I'd be heaven.
You need the JDK 1.4.2 to use ZS3, but there's a version of ZS3 that includes the JDK if you don't already have it.