Back in December, Google announced the launch of aerial imagery for 2 cities in the United States. The high-resolution imagery augments the satellite imagery of Google Earth and the street-level imagery of Street View, giving viewers a look at the ground as if they were flying in a helicopter or some other low-flying aircraft. Originally available only in San Jose and San Diego, both in California, aerial imagery is now also available for Sacramento and Oakland, California, as well as Portland, Oregon.
Travel company Orbitz and online real estate bigwigs Trulia and Redfin have all implemented the new imagery via the Google Maps API. Google Maps Mania also has a collection of mashups demonstrating usage case examples of aerial imagery.