The internet is NOT regulated for content.  Because of this teachers have to be careful about where a student’s internet search might take them.  Creating the perfect, kid friendly search engine has been a goal for some time now.  Above are links to some of the best attempts so far.

Here's another interesting search engine for teachers.  Twurdy.com attempts to sort the search results by reading ability.  This would be particularly useful for finding the easiest to read results for elementary students for example.