This was something I first used successfully when I re-rented Batman Begins after it recently made its return to the Apple TV, the new Chapter selection feature which came with the 2.2 update. I tried using this feature on a few movies I own, including Slacker Uprising which is a newer title, but the option never came up.
The way you get to this feature is you tap up twice, or tap the + sign twice, on the remote while the movie is playing. This brings up an overlay with the description of the movie, and apparently on some titles, the option to Press and hold pause/play for options which leads you to the Chapter Selection screen. I assume that as newer movie titles add features such as director commentary, this will be the area where you will find it.
