A new project has just been released on CodePlex: PHPPowerPoint. Just like with PHPExcel, PHPPowerPoint can be used to generate PPTX files from a PHP application. This can be done by creating an in-memory presentation that consists of slides and different shapes, which can then be written to disk using a writer (of which there’s currently only one for PowerPoint 2007).

Example code and presentation can be found on Maarten Balliauw's blog