Google launched software that allows users of mobile phones and wireless devices to know the approximate location of friends and family instantly.

The feature is called Google Latitude and can be added to the Google Maps application starting from Wednesday. It works on Google's G1 phone, Blackberry's, Windows Mobile devices and several smartphones.

Users can also be in touch directly via SMS, Google Talk, Gmail, or by updating their status message or even upload a new profile photo, Google said in a statement.

The software was added some private features: everything on the program is opt-in meaning each person can control who gets to see their location, decide the location that others' see or sign out of Latitude at any time.

Watch a video below to see how Google Latitude works: