Latitude is a new feature for Google Maps on your mobile device. It's also an iGoogle gadget on your computer. Once you've opted in to Latitude, you can see the approximate location of your friends and loved ones who have decided to share their location with you. So now you can do things like see if your spouse is stuck in traffic on the way home from work, notice that a buddy is in town for the weekend, or take comfort in knowing that a loved one's flight landed safely, despite bad weather.
And with Latitude, not only can you see your friends' locations on a map, but you can also be in touch directly via SMS, Google Talk, Gmail, or by updating your status message; you can even upload a new profile photo on the fly. It's a fun way to feel close to the people you care about.