Over the past year, I have written and referred to many arguments for eating local. If you would like more information, here are some references.
I only have a few minutes - what do I read?
Diet for a sustainable planet. The challenge: Eat locally for a month (You can start practicing now), SF Chronicle
Voting with your fork: Eating local means more for the local economy
Eating local protects us from bioterrorism
I want more!
Coming Home to Eat: the Pleasures and Politics of Local Foods, Gary Paul Nabhan
Eat Here: Homegrown Pleasures in a Global Supermarket, Brian Halweil
Holy Cows and Hog Heaven: The Food Buyer's Guide to Farm Friendly Food, Joel Salatin