You must be an MLB.TV subscriber to fully utilize this app (some features, such as the calendar schedule, are available to everyone for free). There are two annual packages: MLB.TV is $99.95 and MLB.TV Premium is $119.95. If you aren't already a MLB.TV subscriber. The site to sign up will go live later today. Once you've subscribed, link your MLB.TV subscription to a PS3 (via the app), and enjoy the season!
MLB.TV was viewable on a PC, iPhone and iPad, and set-top boxes like the Roku and Boxee. The deal with Sony represents the first of its kind for a video game console, however.
It remains to be seen if similar deals are made with other sports associations. The NHL and NBA have similar PC-based services.
The app is up now under Media, and it is FUCKING AMAZING. DVR functionality, looks perfect on my 55" HD, easy to switch between games, completely awesome.