@Justin_Ross - Sorry for the very late reply.
First off, you will need to purchase a CVLI license (http://us.cvli.com/)
After that, I purchase the movie through itunes, but the movie will have whats called a DRM tag on it which will not allow you to edit it. You will need to run the movie through a program like AVS4MAC M4V converter.
After you run the movie through this converter, you will be able to edit it with most video editing programs.
Hope this helps