I enjoy reading the advice column by Cary Tennis on Salon. He seems sensible. People haven’t changed much since the days of Ann Landers and Dear Abby, but Cary does manage to put a modern spin on things. For example, a lot of his stories have to do with business relationships.
Recently, he posted one on slander by a former co-worker. While I doubt I’ve ever been slandered myself, I’ve seen it happen to others. Cary’s advice was pretty succinct: stick to the facts, and only bring it up with specific people whose opinion you value. He also linked to a couple of other blog posts on the subject I found especially valuable.