Google Latitude is a new feature of Google Maps for mobile devices that lets you see where your friends are by locating them on a map. Of course, everyone has to opt in, so don’t think that you’ll be able to spy on anyone. And you can choose how much information you want to share. Google Talk is integrated so that you can call or instant-message your friends if you see that they're in the vicinity. According to reviews in the Wall Street Journal and Gizmodo, Google Latitude will soon be available for the iPhone.