This is (one of) the million dollar questions this year!
From what I understand so far, and this is from piecing together a lot of responses and a few tidbits of info from the NBA folks......
1. If you have Apple TV you will need to buy the NBA Broadband League Pass. Right now, live games will be FREE until Jan. 8, so you might want to wait and test out the system/picture/etc before you buy.
2. It is sounding more and more like the games on Apple TV will not be streamed live directly to the Apple TV device, as it was last season (like how Netflix works). Instead, you will now be required to have either and: Iphone, Ipod Touch or an Ipad to enable Apple''s Airplay feature to send the game to your Apple TV. You must have iOS 4.0 or later on those devices, so I am guessing if you own an old iPhone or Touch, it's not going to work.
3. There is now an app on iTunes for watching the games live on Apple devices. As I said, the games are free to watch for everyone until Jan. 8.
4. If you purchase the Broadband League Pass and try to log into Apple Tv/NBA right now, it will just give you a log in error. Supposedly, this is going to change on Dec. 25 or 26.
I hope this helps. There is just no info out there right now. It's even more frustrating for those of us that have already paid the $169 for the Pass and cannot log in or get any information.