Rajaa Gulum Abbas
Perhaps the earliest claimed example of supposed 9/11 foreknowledge comes from a man called Rajaa Gulum Abbas, who is often quoted as saying in 1999 that "those towers [the WTC] are coming down". The blog Xymphora said it was "one of the clearest incidents of foresight of September 11", and History Commons covers the story here:
It sounds very clear. But is this exactly what Abbas said? Everyone talks of this tape, but where is it? The MSNBC special here said they'd obtained an audio copy of the meeting, but there's no mention of this comment, or even the World Trade Centre (source). It seems we're relying entirely on the word of (former conman) Randy Glass. And what sites like Xymphora and History Commons aren't telling you is that an early account of the Abbas comment was slightly different:
Here it's not a definitive "those towers are coming down", which implies specific knowledge of an event, just a more general desire to see it "reduced to rubble", which could simply be a wish for a more successful attack on the lines of the 1993 WTC bombing (and keep in mind that not even this version of the Abbas comments has been independently verified).
There may be reasons for this, of course.
Perhaps "those towers are coming down" and "reduced to rubble" are part of the same comment, or maybe two separate statements. History Commons tells us that "this ISI agent later makes two other references to an attack on the WTC", after all (although no-one seems to be able to tell us exactly what they were).
And maybe there's an explanation for why the tape of this meeting seems to have reached the media, but no-one has yet commented on this particular part.
But another possibility is that Glass has made this appear a slightly clearer example of foresight than it really was at the time. Without more evidence, it's hard to tell what the truth might be.