http://twurdy.com/ -- Search engine that ranks sites by reading level
"Twurdy uses text analysis software to "read" each page before it is displayed in the results. Then Twurdy gives each page a readability level. Twurdy then shows the readability level of the page along with a color coded system to help users determine how easy the page will be to understand."
"a search engine that combs only sites that have been reviewed by a team of librarians, teachers, and research experts. There are 35,000 approved websites in all."*