Called "OfficeTalk," the service is described as a vehicle that "applies the base capabilities of microblogging to a business environment, enabling employees to post their thoughts, activities, and potentially valuable information to anyone who might be interested."
OfficeTalk reportedly began as a side project for a few Office Labs workers, and quickly accumulated thousands of users inside the company. Interestingly, Google has been using an internal version of Buzz for "a really long time," according to the company's Brett Slatkin.
Similar services already exist, such as Yammer, so it should be interesting to see where OfficeTalk fits in, but it is still deemed a "research project." Who knows if or when it'll be widely available. In the meantime, Microsoft is looking for a handful of businesses to test OfficeTalk, and you can apply here.