Well, this may not be something that is really known for awhile. Apple could decide to announce new features early, but it is more likely we won't know for sure until iOS 4.2 launches in November and people can test it out in the real world. Of course my opinion on pre-orders is that while the ATV will be pretty popular in the beginning, I doubt they will sell out. I'm sure on launch day, or any other point after that you can walk into any Apple Store or Best Buy and pick one up.