It's been six months since VMware announced vCloud, the company's grand plan for public, private, and hybrid computing clouds. It's almost time for an update on VMware's progress.VMware refers to vCloud as an "initiative," not a new product or platform. It leverages VMware's strength in virtualization, spans corporate data centers and public Web services, and makes room for dozens of partners. The goal is to enable application hosting in the cloud, including multicloud interoperability, using a VMware API called the Cloud vServices API, as well as VMware's implementation of the industry standard Open Virtual Machine Format (OVF), and other VMware technologies.

I talked to Stephen Herrod, VMware's senior VP of R&D and CTO, about what comes next. Herrod wasn't specific on deliverables; VMware is saving the details for VMworld Europe, which runs Feb. 24 to 26 in Cannes, France. But Herrod did say that VMware is developing solutions in three areas: internal or private clouds; public cloud services; and federating multiple clouds.

VMware's work in private clouds entails bringing some of the capabilities of public cloud services, including self-service provisioning and usage-based billing, to the corporate data center. It's also working on securing private clouds by isolating virtual machines in environments where multiple business units share IT resources (which describes most companies).

Herrod acknowledges that some customers already have taken it upon themselves to develop capabilities such as self-provisioning, chargeback, and VM isolation. "A lot of people have scripted this and built it on their own," he says. "It's not a radical new use of the VMware infrastructure."

Part two of VMware's plan is to deliver a software stack for public cloud service providers, companies such as AT&T, Savvis, Terremark, and Telstra that already are VMware users. VMware is developing capabilities to let these providers offer on-demand, subscription services from self-service portals.

The third, and most interesting, area of VMware's cloud strategy is to enable interoperable, hybrid clouds. The company is working on networking, storage, and security to let customers move virtualized data and applications among private and public clouds for replication, cloud bursting, and other usage scenarios.

The big question is when VMware will actually deliver these new capabilities, some of which will be on display at VMworld Europe. We'll have to wait another week for the answer.

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