The National Archives store microfilm of Canadian censuses from the late 1800s. The Provincial Archives store microfilm of birth, marriage, and death records from the same time period.
National Archives of Canada
Index to the 1871 Census in Ontario
Provincial Archives of Ontario
The Ontario Genealogical Society is a volunteer organization. Among their recent projects is a digital index to the 1871 census (availabe at the NAC) and grave transcripts for all cemeteries in Ontario.
Ontario Genealogical Society
Internet directories contain many resources for family historians, including contacts and completed family histories.