First of all, only MSDN Subscribers can access this which they already would
be aware of without the need to post here, next its still BETA software that
is not ready for prime time. Second, its a false alarm:
http://www.news.com/beyond-binary/8301-13860_3-9810189-56.html
Quote:
The software maker erroneously posts a note on its developer site saying a
"release candidate" version of the Vista service pack was being made
available. Microsoft does plan one eventually, but it's not imminent. (From
News.com's Beyond Binary blog.)