Although it's a little late for me, Blizzard has finally launched that which I fervently wished for -- an easy reference guide to all current battlegrounds. The guide clearly explains the purpose of each battleground, what unique elements to look for -- like useful buffs and nodes -- the rules of the game, and most importantly, how to win the thing! Also included are maps of each battleground, so you have a general idea of what to expect once you're inside.
If you've been thinking about giving PvP a try, but been intimidated by the sheer variety of battlegrounds out there to choose from, or just a lack of understanding, take a look at the guides. They do a really good job of explaining everything so that even someone like me that hasn't participated in PvP in years understood what these new battlegrounds are all about. And if you're on your legendary chain and a little confused like I was, wondering what the heck the Temple of Kotmogu is all about, or how to claim a mine cart in Silvershard Mines, the guides have all the explanation you'll ever need.