Microsoft has released details regarding the date on which their E3 2013 Press Conference will begin. June 10th is when the show is scheduled, and those that have been invited have been asked to arrive by 8:45am PT at The Galen Center.
Other conferences from EA and Ubisoft have also been set to occur on the same day, but at later times. Sony, it seems, is the last to announce their own E3 times.