Andrew Penick created this little tutorial: a very useful technique. For those who are making a model, or having multiple views in a scene, set your render window size to something wide and "reserve" different portions for different views like the left side of the window for the overhead view, the center for the camera view, and the right for some special angle.

This is especially helpful if you are doing multiple views in one scene, as in a Myst-like game.

In the overhead view you can see your camera superimposed over the rendered view.