James Cameron's Avatar is coming to iTunes in a special edition that brings its extras up to a level usually seen on Blu-ray. You'll be able to interactively change camera angles and deconstruct the special effects in 17 scenes — though we're guessing that, as with other iTunes Extras, the special content won't work on iOS devices or 1st generation Apple TVs running software older than version 3.0. A simultaneous view (pictured) lets you see the layers under the final product, and a "Green Screen X-Ray" feature shows the original green screen footage behind the special effects of a scene. The iTunes Extras edition also comes with the original screenplay and a gallery of 1,700 images. Preorders start today at $19.99 for HD and $14.99 for SD, and the movie will be available for download on December 20th.