Ron Goldman and Richard P. Gabriel, the authors of Innovation Happens Elsewhere: Open Source as Business Strategy have published their book online.

It describes what open source is, discusses business reasons for using
open source, and describes how an open source project works in a
day-to-day manner. It will help you decide on whether open source is
right for your project, and, if so, what steps you should take to
proceed and some mistakes you should avoid. (via BizzBangBuzz)