Jon Evans releases two novels as free ebooks. Both had previously been paid print releases.
As a side note, both are thrillers - Invisible Armies is about hackers, anti-corporate protestors, globalization, and the surveillance society; Swarm is about fleets of UAVs in The Wrong Hands
"[Blackboard] announced plans to add a 'Share' button that will let professors make those learning materials free and open online."<--stealing the march on Moodle? #irony