Literature Discussion Strategies, Kathy G. Short, California State University, Northridge. Ways to start discussions through novels - could potentially work with narrative texts.
Norms of Collaboration: Annotated, Center for Adaptive Schools. Expansion on the norms of group work, which naturally expands into group discussions.
Teaching with Discussions, The Teaching Center, Washington University in St. Louis. Covers getting started, what to do during the discussion, and afterwards. Has additional resources.