How does it work? Google uses both GPS and cell tower triangulation (a phone's position relative to several cell towers) to pinpoint the users' locations. The technology is already in use on the iPhone when the Google Maps service is used.

I predict that parents will be the most pleased about Latitude, as it provides an easy way to track their children's movements (assuming the children have their phones with them, but who are we kidding?).

Google, who apparently hopes to cash in on location-specific advertising, will be releasing Latitude for Blackberry and Palm devices immediately, and promise to deliver it to the iPhone "very soon". The service is free to users with Google accounts, and works in 27 countries.

I foresee attempts to integrate Latitude with Facebook and Twitter in short order.

I'm sure there will be many privacy advocates who will condemn Latitude, especially if there's no indication by Google how it will use the information. But I prefer to think of the upside: the service will allow for real-life versions of the Scotland Yard board game. How much fun would that be?!

I'll be a guinea pig on this one, and for the sake of science will bully my friends and family into trying Latitude, too. A follow-up report will be filed next week.

Update from MSNBC.com:

"[Latitude] adds a social flavor to Google maps and makes it more fun," said Steve Lee, a Google product manager.

It could also raise privacy concerns, but Google is doing its best to avoid a backlash by requiring each user to manually turn on the tracking software and making it easy to turn off or limit access to the service.

Google also is promising not to retain any information about its users' movements. Only the last location picked up by the tracking service will be stored on Google's computers, Lee said.