HipHop for PHP is now available for download
Facebook had recently announced that they were releasing a project under the open source license.
It was named HipHop for PHP.
Facebook developers said that the initial release might not be stable enough yet for implementation on real life projects.
Facebook however is using a version of this product on their own web service.
HipHop for PHP is designed to speed up PHP based web services (like Facebook) by converting their source code into a self-contained executable.