It looks like the official announcement has finally gone out: The Windows Server virtualization (also known as Codename "Viridian") CTP will be shipping with the soon-to-be-released Windows Server 2008 RC0 build. WSv is a great product so far, and it's been a lot of fun working on it. We've all very excited to see it become available outside of Microsoft.
Once the bits get out in the open, I'll finally be able to start talking about some of the things I've been working on for the past few years.
You'll need a 64-bit VT/Pacifica-enabled machine in order to install and use the Virtualization role, so if you want to use this preview version of WSv, make sure to dust them off ;)