Microsoft's corporate vice-president of corporate communications Frank X Shaw has openly addressed the rumours From Silicon Republic:

Not only has Shaw acknowledged the existence of Windows Blue, he has suggested that the new developments will be revealed this summer. “At Build, developers will see what’s next for Windows, Windows Server, Windows Azure, Visual Studio and more,” he promised, via The Official Microsoft Blog.

Shaw’s post coincided with one from fellow corporate vice-president Steve Guggenheimer announcing that this year’s Build conference will take place in San Francisco on 26-28 June. With this timing, the event will overlap with TechEd, which will take place in Spain on 25-28 June, but Shaw has confirmed that Microsoft will be discussing new products and services at this event also.

 Microsoft VP hints that Windows Blue will be unveiled at Build and TechEd in June