United Nations -- Data on the health indicators related to the Millennium Development Goals is available at http://unstats.un.org/unsd/mi/mi_goals.asp .
World Health Organization-- WHO provides access to searchable data bases and other data sources on disease at http://www.who.int/research/en/ .
World Resources Institute-- The WRI provides free online data in EarthTrends. WRI provides a searchable time-series database with a range of indicators for more than 140 countries. Topics include Population, Health and Human Well-being. The searchable database permits searching for a single indicator but over a full range of countries and years. The result can be downloaded into csv format. The system also provides data tables and country profiles in pdf format, maps and feature stories. The database is available at http://earthtrends.wri.org/ . It is necessary to register to get access to some of the data, but registration is free.
Gapminder -- Gapminder is an innovative data presentation web site which provides dynamic views of data changes over time using bubble graphs. Graphs are available for economic, population, health (including HIV/AIDS), environmental, agricultural and information technology data. Raw data can be downloaded from the site and a desktop version of the software is available free. Users can customize graphs using existing data, but cannot add new data. Much of the data used is from the World Bank and UN organizations. Gapminder is at http://www.gapminder.org .
Data and information specific to the HIV/AIDS epidemic is available on separate pages. For HIV/AIDS time-series data click here. A selection of articles describing the stages of HIV/AIDS and other background information is available here .