Dual Maps is a map creation tool that allows anybody to make an embeddable map that includes a Google Map, a Google Maps Street View and a Virtual Earth Bird's Eye view of the same location.
The maps all work together, so if you change your position in the map the Bird's Eye View and the Street View update to reflect your changed position.
Bird's Eye View
This map places Bing Maps' Bird's Eye View side by side with Google Maps' new Aerial View. The application allows you to compare the Bird's Eye View imagery used in Bing and in Google Maps.