Web Ant : Education and Reference : Encyclopedia and Reference
Encyclopedia and Reference Sites
Nutrition and Food Web Archive 
An education-based nutrition and food website devoted to dietitians, educators, and students.
http://www.nafwa.org
Here you find metric conversion calculators to convert between different units of measurement using the metric, british/american, avoirdupois systems, but also more exotic systems like japanese, ancient greek, biblical and old swedish measures.
http://www.convertunit.com