hints of new iPhone and iPad models. Beta 2 gave us just the ability to delete individual images from your Photo Stream, not to mention hints (as if we needed them) that the iPhone and iPad will eventually be running quad-core processors. This newest beta, as we said, restores the lost 3G toggle setting, as well as updating the baseband firmware from 1.4.00 to 1.5.04.The first beta of iOS 5.1 brought us
The update is available over-the-air for current beta users, and through Apple's developer portal.
source: The Verge