Beta 1 of Virtual Server 2005 R2 service pack 1 is available to download. General availability is expected in calendar Q1 2007. Here's a quick description from Microsoft Connect download site:
It provides improved reliability and performance across mixed workloads by leveraging hardware virtualization assists, high availability for both planned and unplanned downtime and improved support for backup and disaster recovery.
- Intel Virtualization Technology compatibility
- Host Clustering technical white paper and the VB script
- AMD Virtualization compatibility
- Active Directory integration and management features
- Volume Shadow Service (VSS)
- Expanded guest and host OS support
provides users with improved support for backup and disaster recovery. Instead of backing up each virtual machine individually, users will be able to backup just physical machines that will in turn backup all the virtual machines on that physical host.