This news comes during an interview at the Web 2.0 summit. Another thing Balmer said during the interview was "You don’t need to be a computer scientist to use a Windows Phone, but I think you do to use Android."
And it looks like Android has taken the comment quite seriously, with the new UI on Android 4.0 causing the Windows Phone community to question if they are borrowed from Windows Phone.
It has been 8 months since Nokia outlined their plans to use Windows Phone as their primary smartphone operating system. It looks like the time is finally apon us to see the fruits of Nokia's labor in action.