I'm not convinced that Brody wasn't the bomber. Now he's loose. Boom, good storyline for season 3.
Nope, Brody wasn't the bomber. The storyline is all about his conflict between being a terrorist/good person, the writers wouldn't make him actually a terrorist (aside from killing the veep). Also, Carrie pulls him away from the ceremony. There's no way he was going to kill himself in the blast because he wanted to be with Carrie so badly.
My money is on Galvez being the bomber. He dies in the blast and Carrie was suspiscious of him from the start.
Where do Mike and the other marines go from here? Are they content with the video of Brody being a terrorist or do they defend him? Also, how did that video get into the bag that Carrie took in Beirut?