As you suggested, I converted the LR 2 tutorial from mov to m4v files so that they will play on my Apple TV. I have a MacPro 8-core w/12GB RAM and it took almost 34 hours of processing time to convert the segments using QT Pro.
Since the computers can play m4v files, it would be nice to offer them in that format so that the many Apple TV users don't have to go through this intensive conversion process one at a time.
Now that I have them converted, I would be glad to upload them to you, if you're interested, to save you the conversion time.
North Wales, PA