Various tools for writers operated by the ReAnimus Press crew:

How To Improve Your Speculative Fiction Openings, by Robert Qualkinbush
Of Worlds Beyond, by Lloyd Arthur Eshbach, ed.

General:

Specific to Smashwords:

Anthopology 101: Reflections, Inspections and Dissections of SF Anthologies, by Bud Webster
In Search of Wonder, by Damon Knight
Space Travel - A Science Fiction WriterThe Issue at Hand, by James Blish (as William Atheling, Jr.)Having Relationships With Characters on the Road to Great Fiction, by Andrew BurtStaying Alive - A WriterMore Issues at Hand, by James Blish (as William Atheling, Jr.)The Craft of Writing Science Fiction that Sells, by Ben BovaBut Wait.... ThereMemory Blank, by John E. StithThe Winds of Altair, by Ben BovaReckoning Infinity, by John E. StithAmerican Goliath, by Harvey JacobsFetish, by Edward Bryant