I came across this posting, "Create smart playlists in iTunes for audio flashcards", on MacOSXHints today. It has tremendous potential for users or instructors creating a audio exercises. With some careful preparation, you can have phonetic exercises, vocabulary, etc. and they can be listened to at the computer or on the go on your iPod. When I was involved in teaching the Greek program at Brite, each semester we'd make countless cassette tapes of the audio exercises we had recorded for students. This would be a very worthwhile project for a Greek or Hebrew (or theological German/French/Spanish, any language) instructor.
Have a look at the write-up to learn more.
Question: Can't you associate an image with a song? This would allow for visual feedback as well. Just a thought.