Well, there’s another Big Blue on the block.

The official name of the widgetry that Microsoft CEO Steve Ballmer recently called “Windows Cloud” is Windows Azure – (which should grate on IBM) – described by Microsoft’s chief software architect Ray Ozzie at the company’s Professional Developers Conference (PDC) Monday morning as a “scale-out” cloud operating system that will run on virtualized servers in Microsoft’s massive new data centers.

A limited technology preview of the stuff is available and it looks like it will take Microsoft two weeks to get those at the PDC who sign on for the beta up and running.

Microsoft will be running a so-called Azure Services Platform on the Internet-scale OS that developers can use to build applications that scale to the cloud from the beginning and run on Microsoft’s rented on-demand infrastructure.

Microsoft is also promising to put all of its own enterprise software online. (Reportedly a limited web-based version of Office will debut in January.)

Ozzie, who acknowledged that Microsoft was standing on Amazon’s shoulders, claims the grand unfolding vision is a “game changer.”

“It’s a transformation of our software,” he said. “It’s a transformation of our strategy.”

He also said it was still “early days” yet for this transformation, which is meant to counter the advances being made by Google and Amazon and their ilk.

The widgetry will come out in stages and for all practical purposes some of the promised functionality is still at the chalkboard stage. Microsoft gave no indication when Azure would be “baked” and told PDC-goers the widgetry could change depending on their feedback.

It also gave no indication what its hosting prices would be when it gets to the point other than to say they would be “competitive” and that there would be a “variety of service levels.”

It also doesn’t expect its accounts to all go rushing willy-nilly into the cloud – at least it hopes not. It still expects on-premises data centers to remain in place, it said, and perhaps combine with the cloud. It mumbled something about “symmetry.”

Microsoft described the Azure Services Platform as being “built from the ground up,” but users and developers should find it familiar since it recycles basic warm-and-fuzzy Microsoft technologies like the .NET Framework and Visual Studio while making a play for a wider (and perhaps disaffected) audience that might use open source development tools and of course common Internet standards such as HTTP, REST, WS-*, and the Atom Publishing Protocol (AtomPub).

Besides managed code languages that .NET supports, Microsoft says it will add Ruby on Rails and Python – and the open source Eclipse development environment – “in the near future.”

As part of the Azure Services Platform – which is supposed to be interoperable and open – Windows Azure is responsible for the hosting, low-level scalable storage, computation and networking. Infrastructure management is supposed to be completely automated.

And at this point there is also a web-based SQL Services and Microsoft’s Live Services with its 400 million users (think of it as a starter market for Azure apps), as well as something called .NET Services – which is supposed to traverse firewalls and communicate across applications and services, creating federated applications.

Microsoft says SharePoint Services and Dynamic CRM Services will be added soon.

The architecture is supposed to support web applications, applications running on connected devices, PCs, servers and hybrid solutions.

Microsoft has built cloud infrastructures out of shipping containers in Quincy, Washington and San Antonio, Texas and will open others in Chicago and Dublin.

Sanford Bernstein analyst Charles Di Bona estimates that Microsoft has spent $3 billion on the cloud, according to Forbes, which claims the 100-megawatt data center Microsoft is putting in Chicago is bigger than anything Google’s got.