@A Public Place
Thanks Jason and Jolyon.
Many of the legal (US) and ethical issues in photography are discussed in "Legal Handbook for Photographers" by Bert P. Krages. As one might expect, the issues are complex. For starters, there is a body of law concerning the right to photograph and another concerning the use of images. Personally, I ask permission before photographing humans and get model/property releases if I anticipate using an image for financial gain.
The situtation with Google street view is novel and it will be interesting to see how the law evolves. Personally, I like the idea of street view and hope that some accomodation is reached that balances privacy issues with utility. Before traveling to unknown commercial and residential neighborhoods, I have used SV to get a clue. Also, I have used it in my blog to show where an image was taken. Here is an example. (warning: it's a streaker pic)
http://drenaud.blogspot.com/2008/04/far-from-home.html