As I know, itunes music files have drm license protection that can't be played with windows media player, if you want to transfer music from itunes to windows media player, you must convert itunes music files to unprotected mp3
As I know, the music files downloaded from itunes have drm license protection that prevent users playing itunes content on other non-apple mp3 player and cell phone, if you want to put itunes playlists to play on samsung phone, you may need to convert itunes files to mp3.
As I know, the music downloaded from iTunes has DRM protection that prevent users playing itunes tracks on other non-apple players, so if you want to use itunes on a Dsi, you may need to this protected music converter to convert iTunes music files to unprotected AAC for Dsi first:)