Australian Bureau of Statistics: Australian Demographic Statistics
(September 2012)
http://www.abs.gov.au/AUSSTATS/abs@.nsf/allprimarymainfeatures/[...]

This ABS report provides Australian demographic information on the following topics: population change, estimated resident population, population projections, births and deaths, overseas migration, interstate migration, and estimated resident households. See also Population by Age and Sex, Australian States and Territories (Jun 2008 to Jun 2010).
http://www.abs.gov.au/AUSSTATS/abs@.nsf/MF/3201.0

Sustainable Population Australia
http://www.population.org.au/

Sustainable Population Australia (SPA) is an ecological group that is dedicated to increasing public awareness of degradation caused by population growth both globally and in Australia. The SPA website includes a link to world population statistics, as well as Australian national and state population statistics. The site also features media releases, population policies, latest news, opinions, submissions, letters, information on feature books, links to online publications and reports, access to a population discussion group, and information on past and upcoming events.

Australian Government: Department of Immigration and Citizenship
http://www.immi.gov.au

The Australian Government’s Department of Immigration and Citizenship (DIAC) has responsibility for migration, immigration, and citizenship.

United Nations Population Fund (UNFPA)
http://www.unfpa.org

The United Nations Population Fund (UNFPA) is an international development agency supporting countries using population data for policies and programmes in order to reduce poverty and promote health and equality. The website contains extensive information and includes links to a wide range of population issues. See also the United Nations Population Information Network (POPIN), an online resource devoted to international, regional, and national population information (http://www.un.org/popin/).

Development Gateway
Development Gateway is an international nonprofit organization with the mission to reduce poverty and enable change in developing nations through information technology. Visit the Zunia Knowledge Exchange (http://zunia.org), an online community-built database managed by Development Gateway, which is designed to provide information and dialogue on a range of issues with the goal to provide increased access to critical information, greater reliance on local capabilities and more effective international aid.

Population Reference Bureau 
http://www.prb.org

The Population Reference Bureau (PRB) is a collaborative organisation that publishes and disseminates information on population issues. The PRB website contains online access to the quarterly Population Bulletin, the annual World Population Data Sheet, reports, specialised publications, news articles, country profiles, seminars, press conferences, briefings, educational resources guides, and handbooks for journalists, policy makers, educators and researchers. The site also features an online library with serial and reference publications on a wide variety of population issues.