There was an interesting post on Professor Dave Farber's Interesting People (IP) mailing list earlier this month entitled "Steve Jobs' Stanford Commencement Speech". Apparently it's authentic—at least, no one's debunked it yet. It doesn't really matter if they're not Jobs's words, though, since the content seems to be widely acknowledged (on the IP list, at least) as the kind of story Jobs tells about the development of the Mac. Even more interesting than the original post, though, are the numerous follow-ups it generated. (You can read the follow-ups on the June 2005 archive page for the list. As an aside, unfortunately Prof. Farber runs the list by forwarding contributions to the list with altered subject lines, not by moderating submissions with decent mailing list software, so threading of messages is really poor. You'll need to find the follow-ups by searching for "Jobs" on the June 2005 archive page.)
I didn't know the history of the development of the Mac was so controversial, yet I guess I'm not really surprised. In my recent, pre-Mac past, I read "The second coming of Steve Jobs" by Alan Deutschman, a book that paints a reasonably negative picture of Jobs. To read claims that the conventional wisdom (roughly: Jobs visited Xerox PARC, came back to Apple and invented the Mac) is revisionist shouldn't come as a surprise, but, despite most of these claims being a decade or more old, they did. I guess that's the thing about conventional wisdom. Most people believe it.
I gather it doesn't stop there, though. In the last few days, I've read posts by (the late) Jef Raskin, and a response by Bruce Horn. Some of the facts differ in their accounts—and these guys were there at the time. I guess part of the problem is that any development effort like that was certainly a non-linear exercise. It's not just unsurprising that one person can't get the record exactly right, it's not really possible for them to do so. (Except if you're Steve Jobs.)