Microsoft to Debut Windows Phone 7 Next Week Announces Oct. 11 press conference; AT&T will be preferred partner By Kevin Spak, Newser Staff Posted Oct 4, 2010 9:59 AM CDT 9 comments Comments Microsoft executives demonstrate the email interface of Windows Phone 7 during the keynote address to the Tech•Ed 2010 North America conference in New Orleans, June 7, 2010. (AP) (Newser) – Windows is at long last ready to roll out its first Windows Phone 7 device. The company has just sent out formal invitations to the big reveal—an Oct. 11 press conference, CNET reports. Steve Ballmer will be in attendance, accompanied by AT&T Mobility CEO Ralph de la Vega. AT&T will be the preferred partner for the phone, putting Microsoft in direct competition with the iPhone. Executives from T-Mobile will also be there, however, showing off other phones with the OS. Sources tell CNET an early November US launch is expected.