TxCigarMadCap said:
What is a good source to learn the different classes and the subsequent rules associated with those different classes?
The best way to learn, is to go to a match and find a mentor. Depending on the match's you plan on shooting, they may have different rules and classes, then others. I would find a match that is local and attend. Ask questions, and be observant, most benchrest shooters will gladly help someone get started in the sport. Many clubs hold match's that are not sanctioned by major sanctioning body like the NBRSA or IBS, but they most times will follow similar rules, but may modify some of the rules to work with their situation.
Benchrest central is a great place for knowledge, you may want to look around there. As Boyd stated you can find most of the sanctioning bodies on the right side of the page. You will find that the NBRSA (National Benchrest shooters Association) http://nbrsa.org/ and the IBS (International Benchrest shooters)http://www.international-benchrest.com/ have almost identical rules. The problem with shooting Registered match's is this is something you just don't jump into. Registered match's, can be expensive, a bit long, for the beginning shooter, this is why I would recamend a club match first. Register match's don't offer classes for factory guns, making the need for a high end custom gun a must.
I would highly recamend you do some reading and research this winter. My favorite book is a low cost production that can be found on book Sellers, and on-line auctions. That book is Glen Newick's "The Ultimate in Rifle Accuracy." This book was written in the late 1980's, and some of the info is dated, but for a hole it one of the best books on the market. You should be able to pick up a copy for under $10 bucks. http://www.amazon.com/Ultimate-Rifle-Accuracy-Glenn-Newick/dp/0883171597
Glen is a great person, and a great writer, and has a magic way of explaining things. Glens book is a great resource for a weekend shooter that likes to do some "plinking" to the top level competitor.