Here are some important links relating to 4H: 

California State 4-H YDP Website - http://ca4h.org

UC ANR - http://ucanr.org

National 4-H Headquarters (USDA) - http://www.national4-hheadquarters.gov/

County Cooperative Extension Office web site - http://cesanmateo.ucdavis.edu/4-H_Program/