Various tools for writers operated by the ReAnimus Press crew:

SF in Dimension, by Alexei and Cory Panshin
Heinlein in Dimension, by Alexei Panshin

General:

Specific to Smashwords:

Galaxy Magazine: The Dark and the Light Years, by David L. Rosheim
The Issue at Hand, by James Blish (as William Atheling, Jr.)
Anthopology 101: Reflections, Inspections and Dissections of SF Anthologies, by Bud WebsterOf Worlds Beyond, by Lloyd Arthur Eshbach, ed.Having Relationships With Characters on the Road to Great Fiction, by Andrew BurtThe Science Fiction Novel, by Basil Davenport, Robert A. Heinlein, C. M. Kornbluth, Alfred Bester, and Robert BlochThe Craft of Writing Science Fiction that Sells, by Ben BovaStaying Alive - A WriterMore Issues at Hand, by James Blish (as William Atheling, Jr.)Footprints on Sand, by L. Sprague de Camp and Catherine Crook de CampIn Search of Wonder, by Damon KnightHow To Improve Your Speculative Fiction Openings, by Robert QualkinbushModern Science Fiction, by Reginald Bretnor, ed.Heinlein