My friend Lenny send me a request today to follow me around. He sent me a request using Google Latitude. Google Latitude uses Google maps and the GPS functions of your android phone. When you ask your friends to join you on Latitude you can see their location on your Google map. But there is more to the app.
You can use Latitude Alerts to let you know when your friends are near you. You can also keep a history of where you have been and even let people on Google talk know your location status. You can learn all about Google Latitude on the app page.