Mid January 2012 Microsoft announced the System Center 2012 suite. This suite has lots of software tooling for management of an infrastructure. The licensing has been simplified compared to older editions of System Center. There is a standard and enterprise edition which both have the same set of tools (SCOM, DPM, SCVMM etc). The difference is the standard edition can only be used on two virtual machines, the enterprise edition can be used for management of an unlimited number of virtual machines. Both editions are licensed per physical CPU of the virtualization host.
A good overview of System Center 2012 can be found in the posting of Rod Trent titled
New System Center 2012 Suite versioning and licensing model simplifies and excites
While Microsoft Windows Datacenter Edition and System Center suite is licensed per phyical CPU on the host, VMware tooling which enables to run a private cloud has a more complex licensing schema based on number of physical CPU’s and assigned virtual RAM (vSphere) and number of virtual machines to be managed.
Microsoft released a whitepaper titled ” Microsoft Private Cloud A comparative look at Functionality, Benefits, and Economics ” in January 2012 explaining the tooling of System Center 2012 and their licensing compared to the VMware tooling.