But within those generalizations are important details. A good place to start is by checking out the link below. There are also plenty of good books on the topic of communications law. If you're going to write for public consumption, you should buy an up-to-date one and read it.
John's link is from The Poynter Institute's web site about the legal aspects of Blogging, but it also pertains to writing in general.
Link to article on legal aspects of blogging