According to Microsoft's web site
http://www.microsoft.com/windowsserver2008/en/us/licensing-r2.aspx:
Windows Server 2008 R2 Standard – A customer licensed with Windows Server 2008 R2 Standard may run one instance of the server software in the physical operating system environment (POSE) and one instance of the server software in a
virtual operating system environment (VOSE). If the customer is running the instance in the VOSE then the instance running in the POSE can only be used to manage the instance of the OS running in the VOSE.
Windows Server 2008 R2 Enterprise – A customer licensed with Windows Server 2008 R2 Enterprise may run one instance of the server software in the physical operating system environment (POSE) and up to four instances of the server software
in the virtual operating system environment (VOSE). If the customer is running 4 instances in the VOSE then the instance running in the POSE can only be used to manage the 4 instances of the OS running in the VOSE.
Windows Server 2008 R2 for Datacenter – A customer licensed with Windows Server 2008 R2 Datacenter may run one instance of the server software in the physical operating system environment (POSE) and an unlimited number of instances
of the server software in the virtual operating system environment (VOSE).
My question is - do these same rights apply to OEM editions?