Just a quick note. I spotted this nice summary article by Ron Ross over on the Requirements network - Business Rules Come First - and then also noticed that Larry Goldberg had asked an interesting question here - are business rules are an integral part of requirements gathering? I posted my reply but you might like to join in. I have posted before about rules are not requirements but that the same approaches often work for capturing them. If you are interested in rules and requirements you should check out the Requirements Networking Group as it has some good material.