A few minutes ago, in Clive's session at the UK server launch event, our UK product manager announced that later today the Release Candidate of Hyper-V will be available for download.
We committed to "within 180 days of the RTM of Server 2008" for Hyper-V; when we released the Beta before christmas - and ahead of Server's RTM I thought "3 months to RC then" and told people on the date I'd bet on for RTM if pushed. Well the first part has been disturbingly accurate... But the forecast RTM date is a secret known only to a few (and I'm not one of them) and I'm not going to stoke up rumours by saying "I think it release on ..." (probably a Wednesday !)
RC is a big milestone. It's when all the bits are in, the performance is pretty close to final. It's when claims and counterclaims get proved and disproved. I'll post some more details about the update process later on, but the critical thing to search for is KB949219