Microsoft Corp. today announced that “Halo 3” has officially become a global phenomenon, garnering more than $300 million in sales in the first week alone. The critically acclaimed Xbox 360® exclusive, which was released worldwide on Tuesday, Sept. 25, is the fastest-selling video game ever and already one of the most successful entertainment properties in history. Initial reports from retailers worldwide show console sales have more than doubled compared with the weekly average before the launch of “Halo 3.”