Zend is pleased to announce the release of Zend Studio 5.2 - now including a free developer license for Zend Platform allowing you to increase the reliability and maximize the performance of your application before deployment.
I've already downloaded the update and installed. However, it's not clear how you actually get the license for the platform. Hopefully they straighten that out so I can start playing with it.
UPDATE: How to get the Zend Studio Platform and get it licensed.