I used Albief15 and his Emerald Coast Consulting - He was very helpful in making my "B+" answers into "A+" answers. It was the best money I spent in a long time and well worth it. We all think we can answer the questions that come up in an interview - and we can - but it's about giving an answer that reveals more about who YOU are and how YOU think about the situations and your experiences in life that have brought you to this point than the other guys and making yourself stand out from the crowd.
If nothing else, it will give you added confidence and a belief that you have this job before you walk in the door.