MLB.com's At Bat 2009 iPhone App released a major update today that allows subscribers of both MLB.tv and the MLB At Bat app to stream all regular season games via the iPhone. Until today, At Bat subscribers were able to only watch the Game of the Day.
I am a paying subscriber of both and have reviewed both MLB products - in short, the video and audio quality of both services are unparalleled (in fact, no other offering even exists in other sports / leagues). The iPhone streaming is particularly impressive as it occurs both over 3G and Wifi - and the quality is not degraded in the same way that many other mobile video services are.
Hopefully the NFL, NBA and television networks are downloading these apps.