Possible Duplicate:
Get the distance between two geo points
distanceTo(Location dest) or distanceBetween(double startLatitude, double startLongitude, double endLatitude, double endLongitude, float[] results)
is calculate distance for people walk or driving car?
How calculate distance between two coordinates for car?
you can get distance for 2 address by:
http://maps.googleapis.com/maps/api/distancematrix/xml?origins=“+a+”&destinations=”+b+”&mode=driving&language=en-EN&sensor=false
good luck.