Marc Parkel links to a transcript of CNN's "Larry King Live" in which Walter Cronkite said this:

What we just heard. So now the question is basically right now, how will this affect the election? And I have a feeling that it could tilt the election a bit. In fact, I'm a little inclined to think that Karl Rove, the political manager at the White House, who is a very clever man, he probably set up bin Laden to this thing. The advantage to the Republican side is to get rid of, as a principal subject of the campaigns right now, get rid of the whole problem of the al Qaqaa explosive dump. Right now, that, the last couple of days, has, I think, upset the Republican campaign.

Local copy of transcript text here.

Elsewhere there is some speculation about whether the video is genuine, for instance:
http://www.whatreallyhappened.com/osamatape2.html.
This may well be worth pursuing given the doubts about certain previous tapes, but I don't think there's much real evidence.

Much more to the point is the question of whether Bin Laden himself is genuine -- is he really what he appears to be? See above and also:
http://xymphora.blogspot.com/2004/10/bin-laden-timing.html.