Useful and interesting links:

Starting a community garden:

National Kids Gardening Page:
http://www.kidsgardening.com/

Michigan State 4-H Children's Garden:
http://4hgarden.msu.edu/main.html

Cornell University Gardening:

Texas A&M Aggie Kids Hort Page:
http://aggie-horticulture.tamu.edu/kindergarden/kinder.htm

Plants Grow Children Program (from Washington State):
http://benton-franklin.wsu.edu/mg/children/index.htm

Smithsonian Institutions Seeds of Change Garden page:
http://www.mnh.si.edu/garden/

Intergenerational school gardening project:
http://rootsnshoots.go.to/

Growing With Plants (teaching nutrition through gardening education):

Plant a Row for the Hungry:
http://gwaa.org/par/index.html

Dole 5 a Day kids page:
http://www.dole5aday.com/

Education index:
http://www.educationindex.com/

Gardening for Kids (from The Gardening Launch Pad):
http://gardeninglaunchpad.com/kids.html

Growing in the Garden (K-3 Curriculum from Iowa State)
http://www.extension.iastate.edu/GrowingintheGarden/index.html