Over 150 pre-season training games will be available from MLB.com broadcasting from the states of Arizona and Florida. The streaming service is supported on Apple and PC computers, Apple iOS and Android-platform mobile devices, the PlayStation 3, and other devices.
Major League Baseball opening Day is March 31, 2011. By that time all baseball teams are required to carry a roster of no more than 25 players. MLB.com will carry every regular season in HD quality where bandwidth permits.
For a review of MLB.com streaming on the PS3 read this article.
The article states that the streaming service is supported by PS3 among other platforms. I wish that this were true. Unfortunately, Sony has not made the 2011 MLB app available yet. When the mlb.tv app is run, only 2010 and older archived games are available. I was really looking forward to using this service, as I have had a mlb.tv account for years, but I am new to the PS3. I hope that the updated app is made available soon, so I can enjoy the new technology.