About 6-7 years ago Mike Caro was working on a set of rules that he hoped would be adopted to help standardize the different rules used around the country. They were pretty specific and (like USGA golf rules) would be ammendable based on local rules (such as inital buy-ins at the table or cage, etc).

I have not seen any draft in quite a few years but it was very good when I saw it. I'll dig through the old files and see what I have. Over time I think a lot of these rules did becomes defacto standardized - there is still some variation in posting when entering off the button or the 3rd man walking, etc.

Other than that, many (not all) card rooms have the rules available. I remember that Bay 101 used to have a book available at the front that explained the rules for tourneys, ring games, and included the local rules. I once got caught in a local rule regarding a card-down (my fault on two accounts, I dropped the card and then did not understand how I needed to have it returned to the table). My winning hand was declared dead - since then I have made sure that I understand before I start playing.