Other
Population for Countries and Cities Around the World
Site calculates and approximates populations for numerous major cities around the world, and also has information about world countries as well.
US Census Bureau
U.s. Census: Population
This site is great for gathering sociological data. Data can be related to a wide variety of topics. Great for research!
Other
Population Reference Bureau: Country Stats & Reports
This site from the Population Reference Bureau could actually be considered a search engine or the beginning page of a data base. It is a thorough source of information on global population including hyperlinks to organizational sources,...