In addition to the
Windows 8 Consumer Preview, Microsoft has opened access to the download
Windows Server "8" Beta... As far as development progress goes it looks like the new Server platform is still in the '
tick' phase where the Consumer OS has moved into '
tock' as the Server OS offers none of the new Metro or Desktop UI features, components or sub-systems (unconfirmed) but does have new technology like the ReFS file system, performance improvements for for Hyper-V virtual machines, and a Metro-Style Remote Desktop app (which would seem to contraindicate the rumor that the Metro and the "8" Desktop are not included at this time). If someone gives it a whirl before I do be sure and post what ya discover!

Edit: Ars Technical posted a little 'Hands On' article
here...