To remove DRM protection (strip copy protection) from Napster, Yahoo! Music Unlimited and other PlayForSure music services you may use FairUse4WM. It can strip DRM protection from Windows Media 10 and 11 .WMA, .WMV, .ASF audio and video files
http://stream-recorder.com/forum/forumdisplay.php?f=319

Now your legitamately purchased music works on any device you have. No more "you can listen to this music as much as you like...just not on your iPod, and many many music players." You are not limited to PlaysForSure-compatible music players anymore.