This version of watchOS is intended for installation only on devices registered with the Apple Developer Program. Attempting to install this version of watchOS in an unauthorized manner could put your device in an unusable state.
Apple touts that watchOS 3 will bring instant launching of your favorite apps, new performance and navigation enhancements, and tools for fitness, graphics, media and more. More details on watchOS 3 can be found here.
Developers can download watchOS 3 beta 3 from the link below. Please follow iClarified on Twitter, Facebook, Google+, or RSS for updates.