System Center Virtual Machine Manager 2007 has been released to manufacturing.  Key features of SCVMM include:

• Centralized deployment and management of virtual machines
• Intelligent Placement analysis to determine the best servers for virtualization
• Quick physical-to-virtual and virtual-to-virtual conversion
• Ease of use with a familiar interface and seamless integration with other Microsoft products
• Faster deployments with administrator-managed self-service provisioning
• Resource efficiency with server consolidation and increased processor utilization
• Quick automation via PowerShell scripting integration

You can read more here: http://www.microsoft.com/systemcenter/scvmm/default.mspx

And download a trial VHD from here: http://technet.microsoft.com/en-us/scvmm/bb679927.aspx

SCVMM 2007 may be purchased as a component of the Microsoft System Center Server Management Suite Enterprise starting in October, 2007. There is no separate Server license for the management server software, which will be included as part of the Virtual Machine Manager component in the Server Management Suite Enterprise.  Also SCVMM 2007 Workgroup Edition will be available in January 2008.  This is a standalone version that will manage unlimited number of VMs on up to five Virtual Server hosts at a price of $499 per license. 

Cheers,
Ben