MapTool2 from Zorum solutions is a Google Maps mashup that lets you check the elevation of any location in the world. The tool also features a number of other useful features.
The 'area' tool lets you draw a polygon on the map to measure the area of any defined location.
The 'draw polyline' tool allows the user to measure the distance between any two points. There is an option to get an elevation profile for all the vertices on a drawn line. There are also a number of other features, such as the option to get an elevation profile for a given location.
Via: Free Geography Tools & Mapperz