Tectonic has a great blog article by Alastair Otter on 10 Open Source Books Worth Downloading. There is great reading in here for those un-initiated to Open Source software. Now granted a lot of the books are intended for the software junkies like Linux, Linux sysadmin, and Blender. Yet there are still some really good ones that point to how Open Source started and how to implement Open Source initiatives.
The books I recommend the most are The Cathedral and the Bazaar, Free Culture, Free and Open Source Software Development (pdf), Producing Open Source Software - How to run a Successful Free Project (pdf).