Flash Earth is a very cool mashup which lets you enter an address, find a location and switch between several mapping application aerial/satellite views - like Google Maps, Virtual Earth, Yahoo Maps, and more. This is a very handy way to quickly check to see if other aerial databases have a different view of a selected location.
There is something more...Flash Earth can now be used within Google Earth 4.2! As you move around the globe a little white arrow follows you around, simple click it to get an approximation of the current view in FlashEarth in a popup balloon. Click here to download the application.