I came across this little program called Movie2iTunes, it’s a little Freeware app that does just what it says!
It allows you to add any type of movie that Quicktime can play to iTunes, so with the relivant plugins Xvid/Divx and many more.

Drp the app onto your dock or somewhere handy and simply drag and drop your Movie files or Folders containing movie files onto the Movie2iTunes app.

It works by creating QuickTime media links to your movies, it then adds these links to the iTunes library.
It also tries to guess if your movie is infact a TV show, it will correctly set the media type and even try to guess the

season and episode from the file names…

eg. Prison.Break.s01e12.avi

It will automatically match the ‘s’ and ‘e’ if followed by numbers as season and episode nice!

You can download the latest version from:
http://dettmer.maclab.org/movie2itunes.html