Find a Greenmarket in your area:
Go to NYC's Council on the Environment, CENYC's website for a full listing by neighborhood.
Learn more, Do more, Eat more:
Just Food (great information on how to find a CSA to join)
Edible Communities Magazines (check out the Manhattan, Brooklyn, Queens, East End, Jersey, & the Hudson Valley issues to name those closest to NYC)
Local Farms worth checking out and supporting: