At its E3 press event, Sony Computer Entertainment of America opened up a new platform for its PlayStation Store on the PlayStation Network — a movie and TV show download service. It wasn’t announced at the end of the event to create some big closer, and it wasn’t accompanied by a bombastic demo like some of the upcoming games the company previewed (“Resistance 2” frightened me). Nope, the new PSN service had to settle for a few seconds of a trailer for “Walk Hard: The Dewey Cox Story.”