We had a discussion on the Da Vinci Code at church this evening, led by the pastor and by a man who used to be an English teacher who has read and researched some of this same material.
The pastor took the approach that rather than say this book was good or bad, true or false, let's discuss it and use it as an opportunity to learn about the history of the church. Most of the time was spent on early church history and the early Christian writings and how that became the canon, and how Dan Brown used this as fact or fiction in the book.
I think the pastor had an interesting approach. The first topic of discussion was what do we believe. So people contributed several central Christian beliefs and the pastor listed them. Later when some topics came up that were, perhaps, written up as truth in the novel, but may be just from Brown's imagination, the pastor asked, "if these things were true, how would that change our core beliefs?" The answer was clear: our beliefs would remain the same.
The pastor also made an interesting point about Mary Magdalene: If you take a more women-centered view of the Bible than has been traditional, then she is the apostle to the apostles (rather than a nobody or a prostitute.) But if she indeed married Jesus and bore his child, as the book's theme proposes, then she is a notable person because of her husband. In other words, she is "elevated" not for feminist reasons.