(Sample link) NASA for middle-school students http://www.nasa.gov/audience/forstudents/5-8/features/index.html
(Sample link) National Geographic for Kids http://www.nationalgeographic.com/kids/
Textbook resource click on "textbook resources", then click on "Social Studies" then select American Nation, choose 2005 edition of the "survey" text http://www.phschool.com
Geography Games http://www.sheppardsoftware.com/states_experiment_drag-drop_Intermed_State15s_500.html