I'll make an attempt to list new free apocalyptic books once a week. You'll need to jump on these soon too. No telling how long they will remain free for the scarfin'.
1) The Killing Moon by Rod Glenn
2) Caretaker by Richard P. Clem
3) H10N1 by Marsha Cornelius
4) The Virus (The Zero Chronicles) by Aimee Rayne
5) The Apocalypse Blog (Book 0: Before the End) by Melanie Edmonds
6) A Land of Ash by David McAfee, Daniel Arenson, John Fitch V and David Dalglish