Google Earth 4.3 and up has a cool feature that may help landscape or architectural photographers. In the top tool bar is a sun and clouds icon. Clicking it opens a slider which simulates the angle of the sun through the day. If you have the 3D building and Terrain radio boxes checked in the layer section you can see where the shadows will fall in the area you want to photograph at any given time. You can zoom in (scroll wheel), tilt (shift arrow keys) and rotate (Control arrow keys) to find the perspective you may want to shoot from albeit from pretty far away.