Exchange 2007 supported in virtual environments

Great news! – Microsoft has now officially announced support for Exchange Server 2007 in virtual environments, such as Microsoft Hyper-V or any third-party hypervisor that has been validated under the Windows Server Virtualization Validation Program.

What’s supported: Exchange Server 2007 SP1 running on Windows Server 2008
Supported Exchange roles: All except Unified Messaging
What Hypervisor: Microsoft Hyper-V, or any hypervisor validated by MSVVP

More about this from the Exchange Team or Microsoft Support Policies and Recommendations for Exchange Servers in Hardware Virtualization Environments.