Food Composition Tables

Conversions of household measures and serving sizes of various foods into grams.
iDietClub.com.au Food Database (Australia)
(Alan Borushek, Dietitian)
Inventory of European Food Composition Databases and Tables

USDA Nutrient Database (USA)
phyttonutrients, oxalic acid, trans fatty acids http://www.nal.usda.gov/fnic/foodcomp/

Dr Duke's Phytochemical and Ethnobotanical Databases (USA)
(Agricultural Research Service)
Nutrition Data (includes information on food additives) (USA)