The following are sources of microdata or raw data - data that needs to be analysed in a statistical package.
ODESI: Ontario Data Documentation, Extraction Service and Interface
ODESI is a repository of Canadian statistical data, in particular surveys by Statistics Canada released under the Data Liberation Initiative. Health surveys of note include the Canadian Community Health Surveys 2000-2006, the National Population Health Survey 1994-1999, the Joint Canada-U.S. Survey of Health, the Food Expenditure Survey 1984-2001, the 2001 Participation and Activity Limitation Survey (a post-census survey of people with disabilities) and Health Behaviour in School-Aged Children 1997 / 1998.
ICPSR General Archive
ICPSR is the world's largest archive of social science data. The archive is international in scope but most resources are American. The general ICPSR archive contains a number of very relevant health datasets, such as the National Health Interview Survey, done regularly since 1969. Other surveys include the Resources for Enhancing Alzheimer's Caregiver Health study, 1996-2001 and 2001-2004, the National Surveys on Drug Use and Health 1979-2004, and Health Behavior in School-Aged Children, 1996-1998.
ICPSR also contains some special collections of interest, such as the Health and Medical Care Archive (HMCA) and the National Archive of Computerized Data on Aging (NACDA).