As of the 3.2 SDK you can access the view property of MPMoviePlayerController
, modify its frame and add it to your view hierarchy.
MPMoviePlayerController *player = [[MPMoviePlayerController alloc] initWithContentURL:[NSURL fileURLWithPath:url]];
player.view.frame = CGRectMake(184, 200, 400, 300);
[self.view addSubview:player.view];
[player play];
There's an example here: http://www.devx.com/wireless/Article/44642/1954