Geomapping: what a wonderful world!

Suppose you have a set of lat/lon points, where do you find out their elevation? Simple, let say you have the following coordinates (a cross in concrete on the top of the hill in front of my parents' place): 45.469678, 10.970527 (I got these from ‘Get Directions from here’ in google maps) Then call the relevant USGS' web service It says getElevation for Latitude 45.46 –> Y_Value=45.469678 for Longitude 10.