The 18th edition of the world's most classic etiquette reference book, Emily Post's Etiquette, was just introduced by the Emily Post Institute (I call them when I'm stumped). Guess what I'll be making room for on my reference shelf?
If you don't have an etiquette book already, this would be a great addition to your library, especially since it covers topics far beyond weddings. And if it's anything like the earlier editions, it's one of the most helpful books to have around.
They say they've updated for the digital world -- Facebook, e-mail, cell phones. And so I'll leave you to debate this question, which is answered in the book:
Is it wrong for the bride and groom to tweet at their own wedding?