The new beta, build 14C81f, is available through the Software Update mechanism in the Mac App Store and through the Mac Dev Center.
Like OS X 10.10.1, as a minor update, OS X 10.10.2 is likely to bring bug fixes and performance improvements to the operating system. OS X 10.10.1 introduced several reliability enhancements, including improvements to Wi-Fi, but many users have still been reporting issues with Wi-Fi stability in Yosemite.
In the release notes for the third 10.10.2 beta, Apple asks developers to focus on Wi-Fi, indicating the update may fix some of the lingering Wi-Fi problems. Apple also asks developers to focus on Mail and VoiceOver.