Here is the government site to get you started:
http://www.fns.usda.gov/snap/supplemental-nutrition-assistance-program-snap
This website helps to further break down any eligibility concerns you might have and how to apply for food stamps:
http://www.justharvest.org/get-help/snap-food-stamps/
Using this site, you will be able to find out which stores accept food stamps in your area:
http://www.fns.usda.gov/snap/retailerlocator