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, while Whistle Finder is free to download (albeit with some ads) for Android devices. Both apps have the same base purpose: you make a soun