A "History of Filght" supplement in our hometown newspaper today, in honor of the 100th Anniversary of the Wright Brothers' flight, finished with the moon landing, and here's the way the quote appeared, much to my amazement afetr all this discussion:

>Armstrong was first to set foot on the surface, telling millions on Earth who saw and heard him that it was "one small step for (a) man -- one giant leap for mankind."<

I think that's a historically fair way of including the accuracy of what was actually said (or what sounded to be said), what was intended to be said, and what *some folks (ahem) heard (or thought they head) said.
I can live with the parentheticized "a".