Check out the ESPN website and look up Bassmaster. You will see info in there when you dig around on how to become a marshal under the Elite Series stuff. I really have enjoyed it and learned a tremendous amount.
As I have stated before here - the best money I have spent in fishing wasn't my equipment or lures. It has been time purchased with Dave Stewart, money spent to be in a good bass club, and the money I used to be a marshal. With that said, Dave commits all of his time to you while you get smidgets of time with the pros or other club members as they are working to win. Dave gives you knowledge you can use at any lake. I seriously recommend him.
Jason