An event more than a year in the making, Microsoft’s Windows Azure cloud-computing offering is finally available to the public. The software giant announced Azure in October 2008, made the service available as a limited Community Technology Preview (CTP) project shortly thereafter, and has been releasing pricing and product details at a regular clip in the meantime. Preview customers have been experimenting for free with a limited version of Azure, but as of April 1, 2010, all existing CTP customers who have not upgraded to the official version will have their accounts deleted. As the cliché goes, general availability is where the rubber meets the road for Microsoft and its vaunted cloud platform: If it can leverage its existing customer base and convince potential users to trust an oft-criticized software vendor with an entirely new delivery model, Microsoft could become a major force among cloud providers. While Windows Azure is a more-than-capable offering, trust could be an issue for a large number of developers and businesses that don’t believe Microsoft will deliver the openness so valued in the cloud world. Here’s a look at what Azure is, what it costs, and how it fits into (and will differentiate itself in) the market.