Quote from: http://vmware.com/products/vsphere/
VMware vSphere is the next evolutionary step in IT computing; enabling customers to bring the power of cloud computing to their IT infrastructures. Building on the power of VMware® Infrastructure, VMware vSphere dramatically reduces capital and operating costs, and increases control over IT infrastructures while preserving the flexibility to choose any OS, application and hardware.
Build on a proven virtualization platform to provide the foundation for internal and external clouds, using federation and standards to bridge cloud infrastructures—creating a secure private cloud. Organizations of all sizes can achieve the full benefits of cloud computing, delivering the highest levels of application service agreements with the lowest total cost per application workload.
Available in several different editions, VMware vSphere delivers targeted benefits to small business and mid-size and enterprise business customers.
The new vSphere community is already live. Go check it here: http://communities.vmware.com/community/vmtn/vsphere
Before installing (if you have the software) be sure to check the Upgrade Center. You can find more info here: