Microsoft has unveiled a new version of Windows, Azure, designed to work in the suddenly trendy cloud computing environment.

While the traditional version of Windows puts Microsoft's OS onto every client PC -- making apps running on, say, Vista, a headache for large companies to update desktop by desktop -- applications built for Azure will sit on computers hosted at Microsoft data centres.

The company is pitching Windows Azure, and the broader Azure Services Platform that supports it, as an easy way for developers to build applications for the increasingly trendy software-as-a-service market, which sees a program, and all the data created by it, stored online and accessed from any PC or mobile.

Announcing Windows Azure at Microsoft's Professional Developers Conference (PDC) starting today in Los Angeles, Microsoft Chief Technology Officer Ray Ozzie says the new platform would span everything from corporate computing, via hooks to Microsoft's Sharepoint Services and Business Dynamics business intelligence and customer relationship management software, to consumers surfing the web, via Azure's support for Microsoft Live Services, which includes support for sharing photos and other files between PCs and phones.

Mr Ozzie says a "community technology preview" version of Azure had been released, but did not commit to a date for the finished version of the new Windows, and the services platform behind it.