This site is a non-profit, freely browsable database of crimes reported in Chicago.
It is not affiliated with the Chicago Police Department or with Google Maps. It is not an official source of crime information for the city of Chicago. Rather, it is an alternative view of public record that is available elsewhere.
Google maps mashup includes data on population, housing cost, housing market, schools, safety, health, climate, income/work, and age ethnicity for the continental US.
annoyingly, their "explains" don't say where the data comes from, so it's hard to know how up to date it is. However, it's neat.