Various tools for writers operated by the ReAnimus Press crew:

The Craft of Writing Science Fiction that Sells, by Ben Bova
Of Worlds Beyond, by Lloyd Arthur Eshbach, ed.

General:

Specific to Smashwords:

How To Improve Your Speculative Fiction Openings, by Robert Qualkinbush
The Issue at Hand, by James Blish (as William Atheling, Jr.)
Anthopology 101: Reflections, Inspections and Dissections of SF Anthologies, by Bud WebsterHaving Relationships With Characters on the Road to Great Fiction, by Andrew BurtSpace Travel - A Science Fiction WriterMore Issues at Hand, by James Blish (as William Atheling, Jr.)Staying Alive - A WriterIn Search of Wonder, by Damon KnightSister Blood, by Karen HaberBlowdry, by Jerry SohlCompanion to the Cosmos, by John GribbinIf All Else Fails, by Craig StreteBlack Thunder, by Roberta Jean MountjoyBut Wait.... There