If you haven't poked around on Google Earth, you should. It's free, and shows pretty much every square inch of this planet. (Plus it interfaces seamlessly with SketchUp, which enables you to place any model anywhere on earth.)
This link is a bit old, but it contains some pretty amazing views within Google Earth: http://www.pagog.com/2007/08/03/interesting-google-earth-finds/
These views go beyond the typical crop circles most people look for! My favorite is the Arizona farm with an enormouse homage to Oprah Winfrey:
The webpage linked above provides the latitude / longitude coordinates for each view, so you can enter the exact location in Google Earth and check them out for yourself. Very fun!