1. A method for allocating physical storage, networking and computing infrastructure of an enterprise data center as a private virtualized computing environment to a plurality of user groups of the enterprise, the method comprising: allowing access to the private virtualized computing environment via one or more communications networks to the plurality of user groups of the enterprise; providing a user interface for registering the plurality of user groups and submitting requests for virtualized computing services, the private virtualized computing environment instantiated on the physical storage, networking and computing infrastructure of the enterprise data center, the user groups belonging to the enterprise; receiving, from one of the plurality of user groups, a request for virtualized computing services, the request including a request for allocation of a virtualized computing environment; conditionally approving the requested virtualized computing services based on available resources in the physical storage, networking and computing infrastructure and pending tasks in the infrastructure, a maximum capacity of the virtualized computing environment, and an estimated workload to provide the requested virtualized computing services; and allocating and assigning computing infrastructure resources from the physical storage, networking and computing infrastructure, wherein the allocated and assigned computing infrastructure resources comprise portions of the physical storage, networking and computing infrastructure that have a capacity to provide the requested virtualized computing services.