I may have mentioned this unbridled passion of mine before, but since there've been two posts concerning love in the past week, I'll say it again: I. Love. Google. Earth.
Whether it's researching a city on a continent across the globe or a small town just outside Baltimore, Google Earth has been my BFF. We've done so much creeping together. Hours and hours of it. (no, not creeping on people, creeping on places.) I have "walked" down streets of places I have never been through Google Earth Street View.
If setting is essential--or even just a good/semi-important addition--to your plot, Google Earth can tell you what places are residential, what are commercial, what are unoccupied, you can find out what kind of houses in different areas and what the walk between two buildings actually looks like. You can locate restaurants and see pictures by other users.
When I was writing Rain, one of the scenes I utilized Google Earth for the most was a scene at Goodwill Bridge. Google Earth gave me the location and people had posted pictures/panoramas of the view from the bridge at night and during the day. (I even made a wax picture thing in art class of the night panorama.)
If you don't have Google Earth, and plan to set your story someplace on Earth, get it. GET IT.