fwiw, here is how they did it on dc:
someone had to take charge initially, obviously, as the moderator or what have you. they had about one week or so open for nominations of books to read, then a poll was made and open for x number of days. then people had x amount of time to get the book. then they broke it down over the course of a month or so. Read and discuss pages xx-xx week 1, yy-yy week 2 etc. they had someone sort of 'moderate' the discussion - ask questions, etc, but they were trying to get someone different to do each book. you could go back and discuss earlier parts of the book, but no spoilers or jumping ahead in the discussion.
I thought it worked fine, but it's the first and only book club I ever participated in, so I don't have anything to compare it to.