Source -Microsoft has rechristened BizTalk Server 2009 R2 as BizTalk Server 2010, and is now telling customers that the evolution of the product recommends it as a major version versus a minor update. BizTalk Server 2009 R2 was designed mainly to bring to the table support for the company’s latest technologies, including Windows Server 2008 R2, SQL Server 2008 R2 and Visual Studio 2010. According to Arjun Bahree, architect advisor, while the release was initially focused on expanding support, sufficient new features were added throughout the development process in order for the rebranding to BizTalk Server 2010 to make sense, but also to illustrate that customers would be paying for a new major iteration of the product.
BizTalk Server 2009 R2 Rebranded as BizTalk Server 2010 - Still planned for a 2010 release - Softpedia