Here is an interesting video where the presenter runs through the various virtualization scenarios and how to license them:
- Microsoft TechNet Chopsticks: Microsoft Licensing Part 3: Server Virtualization (TechNet for IT Managers)
One of the points made about virtualizing OEM licensed OSs had to do with the inability to move that OEM licensed VM across a cluster. The OEM license is bound to the original hardware, in the case of an Intel Modular Server with 2 nodes, that would mean one or the other node.
The hardware the OEM license is bound to is _not_ the chassis that the OEM OS is running in, it is bound to the CPU, RAM, and Motherboard.
There is also a good explanation of the Server Standard OS 1+1, Enterprise 4+4, and Data Center Unlimited OS licensing.
The video is about 26 minutes and is well worth the time.
Microsoft Small Business Specialists
Co-Author: SBS 2008 Blueprint Book