Ontario, Canada Marriages

If your ancestors were in or near the Ontario area, you may want to look at the excellent records at the Marriage Records section of the Ontario Vital Records Statistics Project. It is worth looking at if your ancestors were from Northern New York as there was frequent travel from NY to Canada and vice versa. The records are seachable by year or by name, and often have the home town of the bride and groom, their parents' names, and the names of witnesses.  This information can be a huge boost to confirming relationships and dates.
This portion of the excellent database can be found at http://homepages.rootsweb.ancestry.com/~maryc/thisisit.htm.