Yes, I saw that a couple of days ago. Take a look at this one:
http://kennethelamb.blogspot.com/2008/02/barak-obama-questions-about-ethnic.html
The definitive clue to that answer is to look at his name, his father's name, and the names of all his ancestors on his father's side. They are all Arabic.
sorry, that post I linked was by RaceBannon.