VMware vSphere is the industrys first cloud operating system,
transforming IT infrastructures into a private clouda collection of
internal clouds federated on-demand to external cloudsdelivering IT
infrastructure as an easily accessible service. Enable the next
generation of flexible, reliable IT services with the efficiency and
low cost of cloud computingfeaturing uncompromising control over
service levels.
  
http://www.vmware.com/products/vsphere/

What's inside:

VMWare ESXi 4.1 update 1 hypervisor,
VMWare vCenter 4.1 update 1,
Keygen (Thanks to MAGNiTUDE)

Enjoy!