Security in-a-box is one of a few toolkits crafted by the Tactical Technology Collective, the same group that did the 10 tactics film highlighted in the post below.
What I like about this toolkit is the way it's written. Each topic has a nicely-written background scenario, like the one below.
Assani is a human rights activist in a Francophone African country. His two teenage children, Salima and Muhindo, have offered to help him with some routine computer work he has been asked to do. After seeing the state of his computer, they offer to teach him the basics of how to keep it healthy and functional. Assani also likes the idea of using Free and Open Source Software, but he's not sure whether that would be more or less secure, so he asks for their advice.
Quite cool, if you ask me.