These are some key links to the environment comunity.
Links to Canadian Environmental Organizations

(Like peeling the layers of a large onion, most of these have numerous additional links)
Networks:

http://www.planetfriendly.net/ecoportal.html
"A guide to environmental directories, portals and networks in Canada and beyond. A great starting point to find environmental groups, organizations, people, places, activities, news, information and opportunity"

http://www.cen-rce.org/eng/index.html
"The Canadian Environmental Network (RCEN) facilitates networking between environmental organizations and others who share its mandate - To Protect The Earth And Promote Ecologically Sound Ways Of Life"

http://www.yen-rej.org/
"The YEN strives to connect Canadian youth environmental groups from coast to coast to coast so that they can empower each other and have more successful local, regional and national environmental action based projects and campaigns"
Special Purpose Environmental Directories:

http://www.planetfriendly.net/living.html
Sustainable Living Guide: "activities and choices that can help sustain your health, your spirit, and the planet. The focus is on positive, constructive things you can do in your home, at work, at school, and at play"

http://www.evergreen.ca/en/resources/registry.html
How Canadians "are making their schools, homes and communities greener"

http://www.alternativesjournal.ca/resources/ugraddir.htm
"A directory of undergraduate and graduate environmental studies programmes at universities across Canada"
Others:

http://www.wildernesscommittee.org/
Founded in 1980, this organization is "the largest membership-based, citizen-funded wilderness preservation organization in Canada"

http://www.sierraclub.ca/
The Sierra Club of Canada has chapters throughout the country. They have four national program areas: health and environment, biodiversity, atmosphere and energy, and sustainable economy

http://www.cape.ca/
"As an organization composed mostly of physicians, CAPE brings its health expertise to environmental issues and is an important voice for environmental health in Canada"