The free ride ends this upcoming winter. The third week of November has been set as the official launch date for commercial services on Windows Azure, Microsoft's platform for deployment of .NET Services to the cloud. This news was delivered by the company's Server and Tools division president Bob Muglia, in an address to its Worldwide Partner Conference in New Orleans.

By stark contrast to other cloud services that utilize Windows, including Amazon EC2, Windows Azure is not the customer's server operating system relocated from the data center to the cloud. Rather, it's a hosting platform for .NET applications that reach global Web customers. Since its announcement last October, developers have been allowed to build and deploy test applications over Azure for no charge. The doors will close as soon as November 17, and developers will be courted to become paying customers.

Those businesses pondering whether 'tis cheaper to deploy services over EC2 or Azure will be busy with their calculators, as the immediate answer is, "It depends."

Basic charges for Windows Azure, announced this morning, will be $0.12 per service hour, with bandwidth charges for Windows Azure and supporting SQL Azure and .NET Services fixed at $0.10 per gigabyte in / $0.15 per gigabyte out. In addition, Microsoft will charge $0.15 per gigabyte of storage per billing period, along with another $0.10 per 10,000 transactions, over and above the bandwidth charge.

What had originally been dubbed "SQL Services," and had at times been called "SQL Server Services," is now being called more succinctly SQL Azure. It's the database service used by .NET Services in the cloud, and for this, Microsoft has chosen to charge a flat monthly rate with a two-tier capacity choice: The "Web Edition" carries a fee of $9.99 and stores up to 1 GB, while the "Business Edition" handles 10 GB for a fee of $99.99 per month.

Transactions over .NET Service will also rack up points on Microsoft's turnstile. Customers will be charged $0.15 per 100,000 Service Bus messages and Access Control tokens per month. What are those? The Service Bus is an intermediary router that provides an endpoint for .NET client applications to contact; it gives Web apps a point of contact for Microsoft's cloud. Once an endpoint is established, services use Access Control tokens to maintain authentication and session state as transactions are being conducted. There's no precedent in other cloud architectures for this type of charge, so today's testers may want to observe just how many of these messages and tokens are generated in an ordinary session, and multiply that by the number of customers they expect to generate...at least while the service is still free.

Microsoft is offering a 99.95% guarantee for compute connectivity, and a 99.9% guarantee for storage, as service-level agreements (SLAs) for customers. It's difficult to precisely compare prices, since Azure's architecture is exclusive. But customers are likely to consider Amazon EC2 as an alternative for deploying Windows services, even though it's essentially Windows Server 2003 in the cloud rather than at the data center. Still, a few of Microsoft's numbers do appear competitive by comparison to EC2: Azure's hourly compute charge just beats Amazon's fee for a "small" footprint machine image ($0.125 per hour), and Amazon offers "large" and "extra large" instances that run much higher.

Azure's bandwidth charges are roughly equivalent to those of EC2, which start higher for data out and gradually become lower (Azure's data-out rate is a flat $0.15). However, Microsoft tacks on an extra $0.10 per 10,000 storage transactions per month, regardless of length.

This morning, Microsoft reiterated its pledge to drive businesses' total cost of ownership for their business applications by up to 60% over a three-year period.