Eastern Market: http://www.easternmarket.net -- not all local farmers, better in the summer on Saturdays. The inside fish, meat and charcuterie counters are amazing, though.

Fresh Farm Local Farmers' Markets: http://www.freshfarmmarket.org

CSAs: http://www.localharvest.org/csa/

http://www.localharvest.org/farmers-markets/M5570