stylesheet
At least in the Boston area, they use a series of cameras mounted on the roof of a Dodge Neon that then drives up and down streets very slowly. Charles Bandes photographed the photographers in Cambridge:
Yes, atop this otherwise unassuming Dodge Neon (from NH of all places) sat four small DSLRs (Canon Rebels?) with super-wide lenses (Sigma 8mm fisheyes?) The car was driving super-slow down the street, with a pattern of backing up and going forward that reminded me very much of a flatbed scanner. The two girls inside seemed like they couldn't decide if they were amused or annoyed that I was following and photographing them as they documented my walk home.
Also see Paul McNamara's take: Did Google's Street View spook even Eric Schmidt?