While it will be a long time before we see a live version of Google Earth, as Frank recently explained, there are some places where small scale real-time imagery is starting to come out.
The most recent example is in Compton, California, where they can monitor a 25 square mile area for six hours at a time thanks to a company called Persistent Surveillance Systems(PSS).
PSS attaches high-resolution cameras to aircraft that fly around and stream the imagery back to the ground. You can learn quite a bit more about it in this video or by reading this blog post on Gizmodo.