Updated: it was real, but Microsoft has pulled the update. According to Hexus.net, the widely-pirated but not-officially-available-yet Windows Vista Service Pack 1 is now ready for download... for some users. The site points out that the update popped today in one of their 64-bit Windows Vista Home Premium systems.
Today however, Windows Update tells me I have one important update to install on my 64bit Windows Vista Home Premium-based system - Windows Vista Service Pack 1 for x64 based Systems (KB936330). Other users don't yet seem to have been prompted for the install and even my own x86-based Vista laptop doesn't have the update available.
Could this be an strange occurrence or a hoax? Any of you have got the same notification? Tell us in the comments. (Yes, wrong headline. Fixed.)
Update: according to news.com, Microsoft is withdrawing SP1 for Vista. 'We've heard a few reports about problems customers may be experiencing as a result of KB937287,' wrote Nick White, Microsoft project manager. 'Immediately after receiving reports of this error, we made the decision to temporarily suspend automatic distribution of the update to avoid further customer impact while we investigate possible causes.'" [Hexus - Thanks Parm Mann and Slashdot]