If you’ve reading this blog for a while , you’ll know that I’m into Business Rules. You know, the logic (formal and informal) that are unique to each company / organisation and govern how an insurance claim gets settled , the price you pay for an airline seat, or how your order from Amazon get’s shipped. Rule Engines are a way of getting this knowledge out of people’s heads and into a computer.
Rules are a very simple idea (you just state what you know to be true), but rule engines are not. Ironically, the problem most people have is ‘this is to simple to work’. If you want to get find out more more, the ‘Down to Earth Business Rules blog’ from Artemis Alliance is a good place to start.
They also have a Squidoo Lens (a set of links to other resources) that is worth looking at.
Paul Browne 
I have a bunch of FAQs about business rules on my blog and post regularly about business rules and other decisioning technologies. The Squidoo lens is a great resource also with a number of other blogs linked from it.
My best bet for finding out about business rules technology is to search for the phrase “business rules” on bloglines, google, technorati, etc. and then subscribing to the search results as a RSS feed.
I also have a page titled Business Rules: An Introduction on my “Business Rules Use-cases” blog. The idea is to give a high-level overview of the benefits of business rules technology – specifically, w.r.t. the kinds of problems it solves in an enterprise scenario.