The FDA's FAQ on Food Irradiation: http://www.fda.gov/opacom/catalog/irradbro.html
The USDA Food Safety Inspection Service FAQ on Food Irradiation http://www.fsis.usda.gov/wps/portal/fsis/topics/food-safety-education/get-answers/food-safety-fact-sheets/production-and-inspection/irradiation-and-food-safety/irradiation-food-safety-faq
CDC Food Irradiation FAQhttp://www.cdc.gov/nczved/divisions/dfbmd/diseases/irradiation_food/
American Council on Science and Healthhttp://acsh.org/?s=food+irradiation&x=22&y=15
WHO Report on Wholesomeness of food irradiated with high doses of radiation.http://www.who.int/foodsafety/publications/fs_management/irradiation/en/
FAO/IAEA International Consulting Group on Food Irradiation FAQ (this links to a PDF)http://www.iaea.org/Publications/Booklets/foodirradiation.pdf
Center for Consumer Research - University of California at Davishttp://ccr.ucdavis.edu/irr/index.shtml