Born Standing Up is a wonderful read. Steve Martin comes across as a very hard working and reflective person, for whom the stars aligned. In the book he is gentle and generous, giving lots of credit to people who influenced him.

In addition to the Smithsonian, the New Yorker ran a piece October 29 2007. The article is not online but there is a short audio clip.
http://www.newyorker.com/online/2007/10/29/071029on_audio_martin