A study like this, just goes to show how meaningless so many "labels" that society has created for groups are. How can someone say "im Christian" and not actually believe in God... that doesn't make any sense.
It's also interesting to see how secular society labels Christians and separates that from an actual belief in Christ, let alone the actual existence of God. They aren't confused about whether or not vegetarians eat meat. that wouldn't make sense. But they have no problem understanding someone who says, "I'm a Christian, but don't believe in God." Faith and values have become a cultural status, not a spiritual one.
I don't know if this is more indicting on the church or our culture. Probably both.
Anyway, it is a very interesting read and it's short, so check it out!
http://channels.netscape.com/news/package.jsp?name=fte/notbelieveingod/notbelieveingod