Just in case folks can't figure out to move or hide the mini widget music player that automattically rendors when moving around apps while you have a music app playing, simply put your finger on the middle of the little widget bar and drag it around the screen and let go when you find the placement that you want.
To hide it completely, simply drag it to one of the outer margins and it will callapse into a little house icon. You can tap that house icon on the screen margin and it will expand the mini widget bar again.