Mark Brown is a Senior Product Manger on the Web Platform team at Microsoft and attended DrupalCon with some news to announce. Not only was Microsoft a Platinum Sponsor of this year's DrupalCon, but they announced that they were releasing a SQL Server Driver for PHP as well as that they have been working with the Commerce Guys on creating a Drupal 7-specific driver for SQL Server that integrates with the new PDO database abstraction layer in Drupal 7. This will make it easier to deploy Drupal on a Microsoft stack of a Windows Server, Internet Information Services (IIS), and SQL Server.
Brown talks about interfacing with the Drupal community and talks about how this project came about from a lot of requests from their customers to make it easier to be able to integrate their Microsoft products with various web application platforms such as Drupal.
Brown also talks about a landing page on Microsoft's site that has more information for how to get up and running with a full Windows stack and Drupal 7 that is located at: http://www.microsoft.com/web/drupal/
On this page, there is a development-preview package of Drupal 7 that includes the PDO for SQL Server, the SQL Server Drupal Module located in the includes/database directory, WinCache 1.1 Beta, a bunch of applied patches, and a few other Drupal modules. It's not quite not production-ready yet, and is advised to only use on test machines.
Check out this DrupalCon presentation for more information on Drupal 7 and Microsoft SQL server.