PHP 5.0 Beta 1 has been released (for a little while now). There's a ton of great content regarding the project's development over at Zend. For those of you not in the know, Zend is the company behind the PHP engine. You can find a todo list for Beta 2, comments on the Beta release, information on the additions to the PHP pcre functionality, and more.
If you want to keep your skills up to date, you better start reading. There are some big changes in the works involving everything from better object oriented functionality, to including more and better Java support. This is going to be a great release.