This UN population information site contains a recent updating of the world population estimates and projections.
This site contains a discussion of world population growth provided by the World Bank.
Here you will find a wealth of material on world population history, as well as projections, provided by the Geography Department of the University of Illinois at Chicago.
Here is another source of information of a number of population facts and the history of the world's population. Provides URLs for a number of population-related web sites.
Demographia.com, a private organization, provides links to number of URLs a history of the U.S. population along with data on the nation's leading cities, with focus on city planning.
This address takes you to the Latin American Population History Bulletin.
The Population Council maintains this page, dedicated to a discussion of population growth.