The offering is the latest in Amazon's Elastic Compute Cloud, or EC2, service, which the company launched out of beta Thursday. As a generally available service, EC2 users can now buy a service-level agreement from Amazon. EC2 has been in beta since August 2006.
"We've listened closely to our customers for the past two years and worked backward from their requirements, adding important new features such as those we are announcing today -- Windows support and a service-level agreement," Peter De Santis, general manager of EC2, said in a statement.
With the new Windows service, Amazon is providing an online environment for deploying ASP.Net Web sites, computing clusters, media transcoding, and other Windows-based applications. Transcoding is the direct digital-to-digital conversion of one audio or video format to another.
Amazon offers EC2 on a pay-as-you-go model with no long-term commitments and no minimum fees. Pricing for using Windows Server begins at 12.5 cents per compute hour. Among the early users of Amazon's Windows service is Autodesk, which is using it as the foundation for its Web-based computer-aided design applications.
Amazon's main competitor in the market for hosted computing services is Rackspace, which announced this week the acquisitions of Slicehost, a provider of hosted virtual servers, and Jungle Disk, a provider of online storage, for a combined $11.5 million.
Amazon dominates the so-called "cloud computing" space, but Rackspace has managed to build a data center of 40,000 dedicated servers for businesses. The company went public earlier this year, and for its second quarter ended June 30, reported net income of $4.2 million on revenue of $130.8 million, with revenue up 58% over the comparable quarter last year.