Microsoft has released Hyper-V RC1 for Windows Server 2008 (X86 , x64) to Microsoft Downloads. Hyper-V RC1 is feature complete, RC1 includes the following added support and functionality:Additional Guest OS support: Hyper-V RC1 adds guest operating system support for Windows 2000 Server SP4 (1-way, emulated only) and Windows 2000 Advanced Server with Service Pack 4 (1-way, emulated only). Simplified install for Windows Server 2008 ICs: With RC1, Hyper-V provides a simplified and consistent process to install the integration components for Windows Server 2008 guests.
Mouse integration support for Linux Integration components: Integration components for supported Novell SUSE 10 Linux operating systems will also include mouse integration support, released simultaneously with Hyper-V RC1. The integration components can be downloaded from http://connect.microsoft.com
The Release Candidate 1 (RC1) update to the Hyper-V role provides improvements to security, stability, performance, user experience, forward compatibility of configurations, and the programming model.
Also available is a remote management update for Windows Vista.
Source:→ Josh's Windows Weblog