Using the ruler tool (in the menu at the top) in Google Earth click between two places. A line appears together with a distance measurement. Save this as a temporary file in Google Earth. Right click on this file in Google Earth and choose "show elevation profile" and a path profile between the 2 spots appears.
|Google Earth path profile|
This does not appear to take any account of the Earth's curvature, so is probably only useful for relatively short distances. Does anyone know how to factor in this?
Looks a useful facility to me for seeing how close to line-of-sight a moderate length path is.