Microsoft's "vendor agnostic" architecture for healthcare applications.
New version: Microsoft Connected Framework version 2
This set of documents details an approach for designing interoperable health care applications using a Service Oriented Architecture or SOA. There is a lot of sophisticated health care domain knowledge contained within this document set, which tells me that Microsoft has done their homework, My guess is that Microsoft is working on a universal healthcare development platform. Sort of like a "Healthcare development operating system" on which to build all other healthcare applications. They started this approach already with Healthvault.