Here is a tool that I could use right now for a couple of clients of my New Jersey Concierges services looking to relocate in New Jersey. MyApartmentMap matches Craigslist listings of Apartments for Rent with corresponding Google Maps. Too bad that this can be used only for some 12 big metropolitan areas right now such us Houston, Boston, Philadelphia and Chicago to name a few. Seattle and Atlanta were recently added so they might not show many listings. You can search by price and number of bedrooms (options are: room for rent, studio and then 1BR to 4BR). In my area, The New York City metro shows a number of New Jersey rentals (using the 'go to suburb' function) but for example nothing in my hometown of Montclair.
Nevertheless a very neat tool, well thought and user friendly.
This is the brainchild of Ian Reardon who started it while looking for a place to rent in Boston, Massachusetts.
I originally read about the service on Monkey Bites.