This Video Goes through how to import terrain from Google Earth and create contour lines. Using SketchUp Pro you can create CAD files as well.
February 14, 2012
I guess there are two ways to import from Google Earth into Google Sketchup. Once uses the import button, the other adds the location. This adds layers to your model, so be aware that you get two new layers, one a 2D satellite view, and the other 3D terrain.