They released it with the new Beta 6 of the iPhone SDK and OS
Before installing and developing with the sixth beta versions of the iPhone OS and SDK, you must first upgrade your Mac system to Mac OS X v10.5.3. To upgrade your Mac, go to System Preferences and select Software Update to install the latest version.
App IDs are a new requirement in provisioning profiles for iPhone OS beta 6. To continue developing, Team Admins will need to create App IDs and regenerate all provisioning profiles. Previously generated provisioning profiles will not work with iPhone OS beta 6.