Google Map Sites
http://www.chicagocrime.org/
Chicago Police Department crime statistics on a Google map, house-hunters in the neighborhood can pinpoint all the sexual assaults in the district between May 19 and April 19 on a single map. With each crime marked by a virtual pushpin, Chicagoans can quickly learn what dangerous train stations, pool rooms and alleys to avoid

www.Cytadia.com
Home buyers can pinpoint the locations of houses in their price range.

www.Housingmaps.com
melds the technologies of Craigslist and Google, to spot available housing in 29 cities including San Francisco, New York, Los Angeles and Chicago for rent

www.ahding.com/cheapgas
which blends Google Maps with data from Gasbuddy.com's database of prices at individual gas stations to see whos the cheapest that day

www.Floridasexualpredators.com
which combines Google Maps with data on convicted sex offenders, can call up maps of their communities and click on the pushpins to see the name, last known address and mug shot of each offender.