Drug War Chronicle. July 13, 2007. Canada: A Majority Favors Marijuana Legalization, But Arrests Are Rising. http://stopthedrugwar.org/chronicle/493/canadians_support_marijuana_legalization_but_arrests_increase
June 2007 Angus Reid poll of Canada: http://www.angus-reid.com/admin/collateral/pdfs/polls/ARS_Drugs.pdf
Quote from the introduction to the Angus Reid poll report: "From June 15 to 18, 2007, Angus Reid Strategies conducted an online survey among a randomly selected, representative sample of 1,028 adult Canadians. The margin of error for the total sample is +3.1%, 19 times out of 20. The results have been statistically weighted according to the most current education, age, gender and region Census data to ensure a sample representative of the entire adult population of Canada. Discrepancies in or between totals are due to rounding."
Home page for Angus Reid Strategies: http://www.angus-reid.com
See also this Canada 2004 poll about cannabis: http://gallery.marihemp.com/2canada