Radley Balko has written extensively on this topic. It is also a frequent topic @ Reason.com. Carlos Miller maintains a blog called "Photography is not a Crim

Radley Balko has written extensively on this topic. It is also a frequent topic @ Reason.com. Carlos Miller maintains a blog called "Photography is not a Crime" that deals with this issue. Those sources are good places to start learning about the ongoing issues of photography in public spaces & of police actions.