Obama and Islam

Via Best of the Web an interesting piece on Obama's childhood.

This raises a question for me. I am in no way questioning Obama's religion or past, but I wonder if this past will prove to be an unexpected problem for him.

And my question is admittedly tied to some degree to a lack of understanding of the details of Islam.

It is my understanding that in Islam, it is considered a capital sin to become an apostate. Those of the radical strain interpret this to mean that apostates should literally be put to death.

My question is, at what point is a person considered a muslim? Is there a minimum age? Are there actions the person must take to be converted? Is there any way that Obama's attendance at mosques as a child would make anybody consider him a muslim at one time? Is there any way that anybody could declare Obama an apostate?

Just curious.

UPDATE: I am behind the curve on this issue. After posting I did a Google search and found that the issue has been raised several times including here. Sorry but I swear I hadn't heard any of this before posting!