An article linked from somebodydial911.com has some interesting tidbits on what will be in PHP5.
PHP version 5, expected to appear in beta form by March, 2003, and released in the summer of 2003, could change all that. Significant performance improvements and a much more complete object-oriented programming environment will allow PHP to provide a powerful Web front end for enterprise-class .NET and J2EE-based applications.