Here's the situation: Your phone is in the room, but you don't know where. These two apps let you yell or whistle to get your phone back. Here's the situation: Your phone is in the room, but you don't know where. There isn't another phone around to call it. How do you find your handset? Two neat apps let you yell or whistle to get your phone back. Marco Polo is a paid app for the iPhone and iPad,