The Citizen Media Law Project states that "knowing your legal rights and responsibilities is important for anyone who publishes online" in the its announcement about its Legal Guide project.  The CMLP's legal guide addresses the legal issues you may encounter as you gather information and publish your work. The guide is intended for use by citizen media creators with or without formal legal training, as well as others with an interest in these issues.  While a work-in-progress, the Legal Guide already provides useful information in its fairly detailed articles. You can browse the Legal Guide section-by-section or search it.  
The same group has an online Legal Threats Database: which contains lawsuits, cease & desist letters, subpoenas, and other legal threats directed at those who engage in online speech.  You can view, search, create, and comment on entries in the database.