What used to be called “RC” (Release Candidate) has been spun to “Preview”, but the meaning remains the same.
Apparently, the W8 RC is planned to be released today. This was “accidentally” revealed in an MS hardware and driver blog post (Chuck Chan, Corporate V.P. Windows Development team), yesterday. The blog post has since been taken down.
Owen Williams nailed the screen shot on Neowin though and here it is:
According to Owen Williams, the W8 Driver Kit will also be made available today.
Check out his article for links which aren’t active yet.
Source:
http://www.neowin.net/news/windows-8-release-preview-to-land-may-31