I hope that you're planning to join us at the Ethos Roundtable on December 18th, when Michelle Murrain will lead a discussion about open source software for nonprofits!
Here's the reading that Michelle has recommended:
"Chapter 4: Philosophical Considerations" (from the NOSI primer for nonprofits)
There's no need to make a reservation to attend Ethos Roundtable events. Just come if you can, and feel free to invite others!