Sprinkled among the other lectures, there will be a few on PHP-related topics as well. This includes ones discussing the Zend Framework, PHP and Webservices, Agile Testing, PHP6 and Unicode, and a talk from Rasmus himself titled Fast and Rich PHP.
The conference will be from June 26th through the 30th in Dublin, Ireland. Registering before May 29th will get you an early bird discount of about 50-60 Euro. After that, prices start at 680 Euro and go up. You can get complete details on the conference and signup online at their site.