Google announced they have added new Street View imagery to Google Maps via Trike view. Trike view is a modified bicycle outfitted with Street View equipment. They can visit locations some cars cannot see.
Here is a sample picture taken with a Trike view.
Note: Google also has snow mobiles for the snowy terrain.
In any event, if you want to see some amazing Google Street View shots, check out 9-eyes.com, you won't be disappointed.