some pretty irrefutable evidence linked from here and quoted as such.
http://en.wikipedia.org/wiki/Osama_bin_laden
In the
2004 Osama bin Laden video, bin Laden abandoned his denials without retracting past statements. In it he told he had personally directed the 19 hijackers.
[7][60] In the 18-minute tape, played on Al-Jazeera, four days before the American presidential election, bin Laden accused U.S. President George W. Bush of negligence on the hijacking of the planes on September 11.
[7]
According to the tapes, bin Laden claimed he was inspired to destroy the World Trade Center after watching the destruction of towers in Lebanon by Israel during the
1982 Lebanon War.
[61]
In two other tapes aired by Al Jazeera in 2006, Osama bin Laden announces,
I am the one in charge of the 19 brothers … I was responsible for entrusting the 19 brothers … with the raids [5 minute audiotape broadcast May 23, 2006],
[62]
and is seen with
Ramzi Binalshibh, as well as two of the 9/11 hijackers,
Hamza al-Ghamdi and
Wail al-Shehri, as they make preparations for the attacks (videotape broadcast September 7, 2006).
[63]
Despite this, bin Laden is reported to have complained as recently as November 2007 of the lack "of evidence admissible in court" tying him and his organization to the 9/11 attack.
[64]