Sharing my own story, hope it helps somebody.
Ihave an iTunes account user and there are gigabites of itunes files on my hard drive. Of course I used to listen to them on iPod. But last month my iPod was broken (sh*t!) and I've got a new zune player on St Valentine's day! Obviously I couldn't copy my M4P collection to it because these file had iTunes DRM protection. Luckily I found M4P converter and converted all my iTunes files just in a few minutes!So I would recommend this M4P converter if you have any problems with protected files - it will convert them to unprotected MP3 or any other format so you can play them without iTunes application.
The url is mp4-converter.info or something like this. Tell me if you need exact will go thru my mail