Microsoft releases SQL Server 2012
Not generally available until 01/04/2012, but you can download it from TechNet/MSDN if you have a subscription or via the links below if you don't mind using the evaluation or Express edition.
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SQL Server 2012 released – The world’s most widely deployed data platform, Microsoft SQL Server 2012, has released to manufacturing (RTM), with an evaluation version available today. General availability will start on April 1. (Source
For anyone using SIMS, SQL Server 2012 isn't officially supported by Capita until the Autumn 2012 release. See resource no. 17910 for details.
Please take note that SQL 2012 licensing is very different from what you are used to and there is a migration path for those with Software Assurance/upgrade rights.
Before you go upgrading your SQL, make sure that your products support SQL Server 2012. Don’t just go assuming that they will, e.g. System Center. (Source