The official Google Blog has announced that its location-based Latitude service is on it's way:

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. [...] Ready to share your location? If you have a mobile smartphone, visit on your phone's web browser to download the latest version of Google Maps for mobile with Latitude. Latitude is available on Blackberry, S60, and Windows Mobile, and will be available on Android in the next few days. We expect it will be coming to the iPhone, through Google Mobile App, very soon.

Interesting that it's coming to the App Store available Google Mobile App (which added the Voice Search feature recently) and not the built in Google Maps app (which Apple develops and would require a firmware release to update).

See the video above for important privacy information. And we have to ask, is this a fun and convenient toy, or the next step towards "Big Brother" all hidden up in "Little Brother" clothes? Is Google parsing all your friends' and family's location useful, or terrifying?