As usual no information detailing changes or new features has been provided.
iPhone SDK 3.1 beta 2 and iPhone OS 3.1 beta 2 are now available on the iPhone Dev Center. These versions are for development and testing only and should be installed on devices dedicated to iPhone OS 3.1 beta software development. Please read the iPhone OS beta Pre-Install Advisory and the iPhone SDK 3.1 beta 2 release notes before downloading and installing.
Use the Apple Bug Reporter if you discover compatibility or functionality issues while testing with the iPhone OS 3.1 beta 2 release.
Please post any changes you find in the comments...