Here is a picture from the workshop on secure communications and anonymous blogging conducted by my colleague Ethan Zuckerman, Dmitri Vitaliev of Frontline Defenders, Wojtek Bogusz of the Tactical Technology Collaborative, and Nart Villeneuve of the Open Net Initiative. These guys are basically the dream geek team for free speech on line. They gave instructions in detail about how non-governmental organizations, human rights groups, and individuals trying to speak the truth under dangerous circumstances can secure their communications and data, and minimize the likelihood that people will get caught or arrested as a result of their work. The second part of the workshop was devoted to anonymous blogging.
Much of the instructions they gave today can be found in the chapters on secure communications and anonymous blogging in the Reporters Without Borders Handbook for Bloggers and Cyberdissidents. (Try here if that link is blocked for you.) Many of the tools they referenced can be found at the NGO-in-a-box website where you can download trustworthy and free software. There are also instructions on how to use these tools and tips about how to be more security-conscious. Also see the Tools & Manuals section from Frontline Defenders.