DropMedia is a fully functional dropbox media player app for iOS:
•Turn your dropbox into a personal cloud media player in seconds
•User log in through dropbox
•Automatically sync with dropbox, so if you remove files from dropbox, it will remove in the app also
•Stream music files (mp3, m4a etc) from dropbox
Or download to your phone for offline listening
•Playlist for all the mp3 or other common sound formats
•You can control through control center