Google is constantly updating imagery in Google Maps. Satellite imagery is relatively easy to come by, Google's got its own satellite for that (OK, technically it's not Google's satellite, but it did fund a big part of it and has exclusive access to it). Aerial imagery, or 45 degree imagery as Google calls it, is a bit harder.
But there's progress in this area, Google is now announcing that it's got new aerial imagery for 13 US locations. The full list is available here.
There's also new imagery in Adelaide in Australia and Cordoba, Argentina. Adelaide is the capital city of the South Australia region and the fifth largest on the continent. It's also dubbed the "City of Churches" for, well, it's many churches. Coincidentally, Cordoba is also sometimes labeled "ciudad de las campanas" or "City of the Bells."