Glenn Reynolds writes a good paper on libel and bloggers from both a legal and a cultural perspective. Wish it were in HTML but the PDF is here.
Also, see the list of legal actions against bloggers maintained most helpfully by Eric Robinson of the Media Law Research Center. And while we’re at it, here‘s my recent Comment is Free post on libel law in the age of the internet. I’m working with folks who are trying to put together a web site that gives you the top 10 things you need to know to stay out of court; stay tuned.