Some time ago I was involved in a proof-of-concept project that had grid computing capabilities as a "nice-to-have feature". At that time we were playing around with web services that were called by the distributor of the grid. Today Microsoft Watch has a nice article about Microsoft Research project around grid computing, code named "BigTop":
Microsoft is working on a skunk-works project that is code-named Bigtop, which is designed to allow developers to create a set of loosely coupled, distributed operating-systems components in a relatively rapid way, according to sources close to the company, who requested anonymity. ... Bigtop consists of three components, all written in C#, according developers who said they were briefed by Microsoft. ... Microsoft Research (MSR) has been dabbling with a variety of distributed OS-related projects for years. more
Although it seems that we have to wait some time (a few years?) for BigTop, it's good to know that MS is working on it!