How can I use Google Maps to let people see each other's locations?

I want to make a program for Andro开发者_Go百科id, what take all people who use my program, on the map. And every other (who use the program) can see her/him. How I can do it?

You will have to have a service up in the cloud. When the user logs in, the app pushes the current location to the server. Then the app pulls down from the service a collection of points.