Debunking 9/11 Debunking
Aside from David Ray Griffin's excellent book, I also highly recommend http://911debunkers.blogspot.com/.
I have followed the scientific literature on the WTC Demolition Investigations and made several videos addressing various scientific evidence that was ignored by the Government Cover-Up (I dare not call it an "Investigation" because that it wasn't!).
I've also helped fuel the ideas that lead to many of Jonathan Cole's videos, which successfully debunked many of the hypotheses put forward by National Geographic and Popular Mechanics.