There was a slight hiccup which meant news appeared, disappeared and then re-appeared. But all the right announcements are posted, notably this one from Taylor Brown on the Virtualization team blog.

Windows Server 2008 Patch KB950049 - the Hyper-V RC-1 update - is available.  

I gave some general guidance about moving between versions and that should all hold for this one. I know what people are asking

(a) Will there be an RC-2 or is the next stop release ? and

(b) When will release be ?

At risk of sounding like a broken record; I don't know the answer to the first, and the answer to the second is we're committed to release by August 2nd (180 days after server 2008 Released) and we're looking good to beat that date: I'm sure there's an office somewhere in Redmond where the wall calendar has the date circled, but as I've said before those who know the date aren't talking and those who talk about it don't know.

Update1 : A new release of the Vista tools to manage Hyper-V is also available.

Update 2: Network World quotes Jeff Woolsey as saying "This is the last planned Hyper-V milestone before RTM."  This had been rumoured but no-one had committed to it that I'm aware of.