The contents from iTunes Store use their exclusive formats like AAC, M4V, M4P, M4A and M4B. Those formats contain "FairPlay" DRM protection. If you can not remove iTunes DRM, you will never play iTunes DRM music or video on any non-Apple portable players. (Like Microsoft Zune, Android phone)

So you just put under the protection of video formats conversion like this site http://imelfin.com/video-converter.html can Lets you legally remove DRM protection from WMV, M4V, WMA, M4P, M4B, AA and more files downloaded or purchased from iTunes.