Microsoft has appointed Terry Myerson, who previously oversaw the phone group’s engineering efforts, as its new Windows Phone Division President. The appointment – which was communicated by a letter sent to employees by CEO Steve Ballmer – comes after the holder of the position since 2009, Andy Lees, was appointed to a new role in the company’s phone and PC business. According to Reuters, Ballmer wrote that Lees will work on “a time-critical opportunity focused on driving maximum impact in 2012 with Windows Phone and Windows 8.”