Microsoft is looking spread the reach of its fledgling Windows Azure cloud-computing initiative with the announcement of a "platform appliance" that its industry partners and large customers will be able to use to run the company's Windows Azure service in their own data centers.

To be clear, this is not the Maytag in your garage. Microsoft says the idea is to let businesses use Windows Azure to run hundreds or, in some cases, thousands of computer servers for themselves (in the case of big businesses) or for their own customers (in the case of Microsoft's partners) when issues such as regulatory compliance or a need for physical proximity keep them from using Microsoft's own remote data centers.

The initiative has won support from eBay, the online auction and e-commerce giant, which Microsoft describes as an early customer of the Windows Azure platform appliance. Microsoft says partners Dell, Fujitsu and Hewlett-Packard will also start with an initial "limited production release" of the platform appliance in their data centers, to be able to offer Windows Azure to their own customers.

Microsoft says the appliance is essentially the same platform it runs internally -- including Windows Azure and the SQL Azure database running on Microsoft-specified hardware. One benefit is the ability to scale up and run programs across many machines simultaneously. The idea is to let companies "deploy the cloud on their terms," said Amy Barzdukas, general manager in Microsoft's Server & Tools Business.

The Azure appliance is being announced this morning at Microsoft's Worldwide Partner Conference in Washington, D.C., where the company is meeting with the thousands of partners who resell, deploy and support its products. Microsoft CEO Steve Ballmer also addressed the conference this morning, stressing the importance of cloud computing in his comments, available via webcast.

"If you don’t want to move to the cloud, we’re not your folks," he said.

In general, cloud computing is the concept of accessing computing storage and processing remotely, over the Internet, rather than from a local computer or server. Microsoft launched Windows Azure commercially earlier this year, playing catchup to Google, Amazon.com and others. Cloud computing represents a change from Microsoft's traditional PC and computer server software, raising the risk of cannibalizing those businesses, but Ballmer said this morning that he believes "smart" local machines such as Windows PCs will continue to play a key role, working in conjunction with cloud-computing services.

At the same time, Microsoft is also touting its traditional Windows Server software for running cloud computing services, saying it allows for greater customization than a standardized service such as Windows Azure or the new Azure appliance.

With the announcement of the appliance, Microsoft is trying to give itself a foothold in the "private cloud," essentially letting its customers use its cloud computing technology for their own clouds. The company didn't announce specific pricing plans.

Follow-up: Ballmer: Microsoft is hardcore about Windows 7 slate machines

Update: In other news from the conference, Microsoft announced an expansion of its beta for Windows Intune, its online service for managing and securing PCs. The company also said it would be pricing the service at $11 per month per PC when it's publicly released. New features include the ability for Microsoft partners to use the Intune dashboard to manage computers for multiple customers at once.

See this earlier story for more on Windows Intune.