iFlipbook and iFlipbook Lite went into review today. Unfortunately it looks like Apple had a problem with the Game Center integration.
Their response: Game Center information, such as Leaderboard scores, may only be used in apps approved for use with the Game Center
Apparently whoever reviewed it did not realize that multiplayer fully utilizes Game Center. Soooo, I have resubmitted both versions with an explaination and sent in a request for expedited review. We'll see what happens