Getting Started - What Type of Book Club?
First of all, you should think about the type of book club you want to start.
Will you meet together in someone's home or neutral site? Or do you plan to start an online book club where everyone stays in contact via e-mail? (I know of two groups doing this very thing: one a group of friends and one family group. (Try http://www.freebielist.com/messageboards.htm)
Will your group include women only, men only, will it be coed, seniors or generational? If you plan a coed group remember to choose titles that will be enjoyable reading for both men and women. (You can even start a book club for teens. Check Teenreads.com for good lists of titles.)
Will you read certain kinds of books such as Best Sellers, Classics, Award Winners or Oprah's picks, or will you read all over the board?
Do you intend your book group meetings be fun, relaxed events or do you want them to be more formal such as a classroom setting while you discuss scholarly or literary works using Robert's Rules of Order Newly Revised in Brief 
A new type of reading group proving very successful is where the members all read a book of their choice rather than the same book. They meet for coffee or lunch and discuss a book they have just read, or one they are currently reading. This is a good way to pick up lots of good reading suggestions. It's fun, too! (Members cam take turns compiling the list of titles discussed and send it to the rest of the group.)
Think about starting a multi-generational book group! We can pass on the joy of reading to our grandchildren by forming a special book club consisting of grandparents and grandchildren. The grandchildren should be in the same grade level (6th or 7th grade) so the book is appropriate to their grade/age level. Then the book can be shared and enjoyed by grandparent and grandchild.
A new type of book club recently in the news is a "faith club" where members are Christians, Jews, or Muslims. Read The Faith Club: A Muslim, A Christian, A Jew-- Three Women Search for Understanding
If you are thinking of joining an established book club, be sure to check out all the about mentioned points or you could find yourself in a group not to your liking and you'll be disappointed!
Who Will You Invite? Getting Started