Amazon's Elastic Compute Cloud (EC2) - it's Linux-based one - has moved to production status after two years in beta and now offers a 99.5% Service Level Agreement (SLA) while a Windows one, running Windows Server and SQL, both 32- and 64-bit, has gone into public beta to meet customer demand.

Amazon says EC2 can now be used to deploy ASP.NET web sites, high-performance computing clusters, media transcoding solutions and other Windows-based applications. Pricing for the Windows cloud starts at 12-and-a-half cents a compute hour.

Meanwhile, the EC2 SLA, which is meant to instill confidence in the cloud's endurance, guarantees 99.95% availability over a trailing 365 day period within what is called a Region, or else customers are eligible for credits back. Currently there's only one Region but Amazon is expecting that to change.

A Region is divided into so-called Availability Zones and the way the SLA works a Region is unavailable if more than one of its Availability Zones can't be accessed from outside.

The Simple Storage Service (S3) side of Amazon's cloud already offers a SLA, lucky too because it's gone down in the past.

Amazon is promising new features next year like load balancing to even out incoming requests and distribute traffic across multiple EC2 compute instances; auto-scaling to automatically grow and shrink EC2 compute capacity on-demand based on application requirements; real-time monitoring of EC2's operational metrics for better visibility across multiple instances along with the ability to aggregate them; and an interactive management console with a simple point-and-click web interface so customers can manage and access their AWS cloud resources and get a global picture of the environment.

Oh, by the way, the Windows EC2 is accessed via Windows Remote Desktop or the rdesktop client.

The news came within hours of Amazon sending a shiver through what's laughingly called the economy because it took down its Q4 guidance, seen as a barometer of customer spending.

It's now expecting full-year revenues of between $18.46 billion and $19.46 billion rather $19.35 billion-$20.1 billion with sales this quarter growing anywhere from 6%-23%, a big spread indicative of companies' limited visibility.

In Q3 Amazon's revenues were up 31% to $4.26 billion and its earnings were up 48% to $118 million.

The downturn of course is expected to push more cloud use as a cost control, skipping like a stone across the IT industry. Folks like Eli Lilly and Autodesk are using EC2.