In his attempts to discover truth, Socrates would question people to discover what they knew (and didn't know).  Teachers can use Socrates' method in the classroom by acting as a faciliatator and asking questions of the students.  Rather than appearing as though they had all the answers or encouraging students to guess the "right" answer, these teachers encourage their students to question their own thoughts and beliefs on the topic at hand.

Socratic Method Lesson Plan
This site details methods a teacher can use to conduct a Socratic seminar with his/her students.

The Socratic Method: Teaching by Asking instead of Telling
This is an article featuring a transcript of a Socratic dialogue with a third grade class.