ConvertMovieToAudio is a free Automator action to extract PCM audio as .AIFF format from Quicktime movie files. ConvertMovieToAudio is useful when you want to put downloaded movies into iTunes.
Place "Extract audio from movie files.action" file into one of the folder below (if you can not find the folder, please create it yourself):
. for limited user only: /Users//Library/Automator/
. for system wide use: /Library/Automator/
Then launch Automator. The action should be listed somewhere in the Music category.