(Sample link) NASA for high school students http://www.nasa.gov/audience/forstudents/9-12/features/index.html
(Sample link) National Geographic http://www.nationalgeographic.com
Great site for helping you in completing your science fair projects!! http://www.sciencebuddies.org
This link has the official information for all city schools' science fair. Pay particular attention to the checklist and format that all projects must adhere to. http://cpsscifair.org/