Ancestry - Great website for doing searches and to post your family tree.
RootsChat - Excellent forum site, would definately check out the "chatterbox" - one of the best chatrooms out there.
Collections Canada - Library & Archives of Canada
Ontario Vital Statistics Project - Transcriptions of births, deaths and marriage for Ontario
Northen Ontario Gravemarker Gallery - Photos of gravestones from all over Northern Ontario
Automated Genealogy - Canadian Censuses