The third beta of iOS 6.1 has been released to developers, edging closer to a wider public release for the minor software update. iOS 6.1 beta 3 arrives as build 10B5117b and is available as an OTA update to anyone currently running iOS 6.1 beta 2. IPSW for beta 3 will also be available for downloading from the iOS Developer Center.
Thus far, no significant changes have been found in iOS 6.1 betas, and the release primarily consists of minor improvements to Maps, Passbook, Siri, and Safari, as well as a variety of bug fixes and minor UI adjustments.
Those who are not developers but interested in learning more about the beta can read some more details at MacRumors.