I just found on the net that the 9-11 commission has posted their final report on the internet. It's like 500 pages long in PDF format... I don't know how credible the site is... but it's interesting to read... I've only read the first 10 pages or so.
http://www.9-11commission.gov/report/911Report.pdf
http://www.9-11commission.gov/report/911Report.pdf