Daniel Savarese has a nice article in the July issue of JavaPro magazine about business rules and logic programming. The source code for the article is also available online (by following that link).
They also have an interesting article titled "A Design Pattern for a Rule Engine", but in that case I am more interested in the resources that they refer to than the article itself. Since I can't easily bookmark those links, I'll copy the interesting ones here:
The second link, in particular, has links to many other interesting resources.