Numbeo
http://www.numbeo.com/Numbeo is the biggest free database of user contributed data about cities worldwide
Numbeo is the biggest free database of user contributed data about cities and countries worldwide, especially living conditions: cost of living, housing indicators, health care systems, traffic, crime and pollution. Numbeo is a collection of Web pages containing numerical and other itemizable data about cities and countries, designed to enable anyone to contribute or modify content. Numbeo uses wisdom of the crowd to get as reliable data as possible.