Kidtopia - a Google Custom search engine
"Like Infotopia.info, created by Dr Michael Bell, Kidtopia is a Google Custom search engine of SELECTED sites. Like Infotopia, Kidtopia includes only sites previously recommended by librarians and teachers. Like Infotopia, Kidtopia is also free.
Kidtopia, however, is aimed at providing information for lower and middle elementary students, while Infotopia serves upper elementary, middle, and some high school."