Public Service Commission of Canada's Federal Job Site

Extensive listing of government positions in a variety of fields. Includes regional job information.
http://jobs.gc.ca/

Canada Post Employment Opportunities

Categorized according to technical, mail operations, professional and administration fields.
http://www.canadapost.ca/CPC2/admin/hr/jobs/eomain.html

Government Jobs Canada

Guide to Canadian federal, provincial and municipal government jobs.
http://www.pse-net.com/joblistings/joblistingCan.htm

NRC Careers

Currently available positions at the National Research Council open to the general public.
http://careers-carrieres.nrc-cnrc.gc.ca/Careers/career_main.nsf/pagee/JobsAvailableNow.html