Google's not just going for Street View's of the enitre Earth, Lunar Street View coverage isn't too far away.
On Google Moon, there are many placemarks available in the Apollo layer, including Street View for a few locations:
Apollo 11: Placemark 10
Apollo 12: Pacemark 6
Apollo 14: Placemark 10
Apollo 15: Placemark 3
Apollo 16: Placemark 8
Apollo 17: Placemark 5
Okay, it's not technically a Street View, but it works much like the Street View here on Earth. You can pan, zoom in and out, and there's an astronaut similar to Street View Guy.
What's next? Well, possibly a way to link to these like on Google Maps, and hopefully these panoramas on Google Moon API. Hey, it's one small step for a man, right?