So, I get this question all of the time. How do I make sure that I am appropriately licensed to run Microsoft OSs in my VMware VMs. Can't I just have the number of licenses purchased for all the VMs I am going to run, and then it doesn't matter where I place them? Also, how do I account for VMotion?
Well, you can't just buy all the licenses necessary for the VMs that you have because you have to physically assign the licenses to a physical entity. Plus, there are different types of licenses (Standard, Enterprise, Data Center Edition) and depending on which one you buy will allow you to run 1, 4, or unlimited virtual machines on that box.
Now I am not a Microsoft Employee, and anything you read here is my opinion and shouldn't be used as legal documentation. You should always consult your Microsoft Sales Representative, but I feel this is accurate when considering simply the Microsoft OS licenses, it doesn't cover the Applications at all.
Microsoft has posted some Windows Server Virtualization Calculators that you can use to help determine what licensing you need, and I have posted a You!Tube that tries to demystify this whole thing. Check out my Hey Dad - Microsoft Virtual Machine Licensing Policies video.
Let me know what you think.