The Passbook support works for AT&T Park, Citi Field, Fenway Park and Kauffman Stadium, the only four that have rolled out ticketing this season. The MLB hopes to expand support for this feature to all parks next season.
In addition, the price of unlocking all of the features of the app including live stats and Gameday audio drops to $3.99, a buck more than the monthly price.
It really is one of the best sports apps on the iPhone, period. If you’re getting an iPhone 5 tomorrow, this will be a good one to try out on it.