// instantiate a music player
MPMusicPlayerController *iPodMediaPlayer;
iPodMediaPlayer = [MPMusicPlayerController iPodMusicPlayer];

// Check if it is now playing
if([iPodMediaPlayer nowPlayingItem]){
    NSLog(@"iPod is playing");
		
    // Get the now playing item
    MPMediaItem *nowPlayingMediaItem = [iPodMediaPlayer nowPlayingItem];	

    // Get info of the item
    NSString *itemTitle = [nowPlayingMediaItem valueForProperty: MPMediaItemPropertyTitle];
    NSString *itemArtist = [nowPlayingMediaItem valueForProperty: MPMediaItemPropertyArtist];

    NSLog([[NSString alloc] initWithFormat:@"playing: %@ by %@", itemTitle, itemArtist]);
		
		
    } else {
	NSLog(@"iPod is not plaing");
    }

http://developer.apple.com/iphone/library/documentation/Audio/Conceptual/iPodLibraryAccess_Guide/UsingMediaPlayback/UsingMediaPlayback.html#//apple_ref/doc/uid/TP40008765-CH100-SW1

Retrieve info of the now playing media item in iPod

iPhone