Increasingly, school librarians feel a need for their students to access alternative search engines as safe alternatives to Google and the other standard general search engines. One way to do this is to make available collections of vetted or "juried" sites, many times selected by other educators and librarians. Some of my favorite such sites for secondary school students include the Internet Public Library (http://www.ipl.org/), Digital Librarian (http://www.digital-librarian.com/), and BUBL (http://bubl.ac.uk/).
There exist search engines on the Internet that search only sites similar to the three listed above. A lot of these are Google Custom Search engines, free to anyone who wants to sign up at http://www.google.com/cse/ . One such search engine is Infotopia, a Google CSE that I created last November 13, 2009.
Infotopia, http://www.infotopia.info , searches only sites previously selected by librarians, teachers, and educational and library consortia. I have designed Infotopia to search with Google Safe Search always on. No filtering needed, and you get all of the precision and search features of the regular Google search engine.