Obama and Religion

As part of a ridiculous smear job regarding Obama's schooling at a Muslim school, I came across the following passages quoted from his book:

In both of his autobiographies, Mr. Obama characterizes himself as a Christian—although he describes his upbringing as mostly secular.

In “The Audacity of Hope,” Mr. Obama says, "I was not raised in a religious household." He describes his mother as secular, but says she had copies of the Bible, the Koran and the Bhagavad Gita in their home.

Mr. Obama says his father was "raised a Muslim, but by the time he met my mother he was a confirmed atheist...." Mr. Obama also describes his father as largely absent from his life. He says his Indonesian stepfather was "skeptical" about religion and "saw religion as not particularly useful in the practical business of making one's way in the world ...."

In the book, Mr. Obama briefly addresses his education in Indonesia. "During the five years that we would live with my stepfather in Indonesia, I was sent first to a neighborhood Catholic school and then to a predominantly Muslim school; in both cases, my mother was less concerned with me learning the catechism or puzzling out the meaning of the muezzin's call to evening prayer than she was with whether I was properly learning my multiplication tables."

I'm definitely curious to hear more about his religion. Just how did he come to his current religious views?