what is transparent modal window with playback controls in iPhone Music Player (iPod)? how can i use it in my application?
You can view and control iPod playback via [MPMusicPlayerController iPodMusicPlayer] , but there MPVolumeView are no built-in controls next to it that you can display in your app. You will need to create your own custom view.
[MPMusicPlayerController iPodMusicPlayer]
MPVolumeView