Crypto-Squad by Jason Brannon and Eric S. Brown is free...
http://www.amazon.com/Crypto-Squad-ebook/dp/B009G4BI7A
I was psyched to see this one for free because it was on my wishlist. Eric S. Brown is a really popular indie author. I'm reading one of his Bigfoot novels right now.
Here is an interview with Eric S. Brown by the really nifty Rue Morgue magazine:
http://www.rue-morgue.com/2011/12/mo...-eric-s-brown/