Look what I found on eMusic- Richard Feynman
The Pleasure Of Finding Things Out by Richard Phillips Feynman
I'm not a big audiobook guy, but I do drive to work, so it might not be a bad idea to occasionally flex my brain a little bit on the drive. Especially if it's Feynman doing the flexing. If he were around today literally everything he published would be dugg or reddited.
You can also find lots of interviews with Feynman and some of his lectures on YouTube.