Fox confirmed at today’s Upfronts that the Simpsons/Family Guy crossover episode, “The Simpsons Guy,” will air in September. The Griffins end up in Springfield and pair off with their Simpsons counterparts. Stewie becomes obsessed with Bart. Lisa befriends Meg. Marge and Lois bond. Peter and Homer fight over which beer is better: Pawtucket or Duff.