There are several links that I want to highlight about open source software in general. First there is the ongoing "A history of Free and Open Source by Peter H. Salus, who is serialising the book in Groklaw. Here is the introduction. Then there is a good article about the SCO case by Groklaw's Pam Jones. Then (courtesy of Anne-Kathrin Kuehnel), there is this online book in Spanish called "Software libre; técnicamente viable, económicamente sostenible y socialmente justo" by Jordi Mas i Hernández. Looks like a good introduction, but it is a bit basic for those already familiar with the subject.