AppleSeed is a program that lets selected users receive early access to software for testing purposes.
An email sent to participants today reads:
You are invited to participate in the next Mountain Lion Software Update seed project, 10.8.2. Apple will provide you with the pre-release software. Once builds are available, we ask that you install and test each build to help us make sure that this is a high quality release!
What's new in 10.8.2 is not yet known. The 10.8.1 update is said to significantly improve battery life and should be released soon.