Alongside the iOS 4.3 update, Apple TV received several new feature updates this afternoon, including live streaming sports from MLB.TV and NBA League Pass, AirPlay enhancements, and 5.1 Dolby Digital audio on some streaming Netflix titles.
The addition of MLB.TV and NBA League Pass is a significant upgrade, as they represent some of the first non-iTunes streaming media services available on Apple TV, aside from Netflix and YouTube. The lack of additional streaming media services has been one of the our major criticisms of Apple's streaming video box, as competitors like the Roku XDS have offered MLB.TV and NBA (along with tons of other services) for quite some time.
As on any other platform, MLB.TV and NBA League Pass will only stream live games to out-of-market customers, so it's not exactly a replacement for hometown sports fans looking to ditch their cable subscriptions.
We'll be updating with more details after some hands-on time with the new software.