Cornell University reproduces the well-known pamphlet "Facilitating Discussion: A Brief Guide" by Katherine K. Gottschalk, which contains pointers on establishing rapport, Leading Discussions involving the entire class, and small group strategies.
This is an in-depth look at the process of Asking and Answering Questions, adapted from the book of the same name by Cashin et al.
Communication Skills for Leading Discussions includes tips for improving communication and discussion skills.
This multipage Guide to Classroom Discussions is authored by two PhDs who write curricula and give workshops on educational technologies.
Discussion Skills for Tutorials and Seminars contains a list of tips for increasing the value of discussions by communicating effectively and respectfully.
Managing Hot Moments in the Classroom offers strategies on how to keep classroom discussions under control.
Iowa State University's Center for Excellence In Learning and Teaching offers Suggestions for Leading Small Group Discussions.