Update: Google Maps Labs now contains some aerial imagery. Please expand this article to include accessing that imagery.
Google recently released a product called 'Google Building Maker' which uses aerial imagery taken in select cities to create 3D models of buildings.
This article discusses how the aerial imagery can be retrieved.
Firstly, each location will have multiple images (e.g. different orientations and angles), and the list of the images for a specified latitude and longitude can be found by navigating to:
The imagery is available in tiles similar to Google Maps, so once you have picked a image_id, retrieve each tile with:
Use the zoom, x and y parameters to get all tiles for the zoom level.
Zoom 0 & Zoom 1 has a black region as the image is smaller than the tile.
Zoom 5 is the maximum zoom level.