There was nano thermite found in the dust of the towers. That is really the only evidence you need to acknowledge that there were explosives in the towers.
The video is really interesting. Live callers call into CSPAN and want answers to all of this hard evidence. They will not answer any of the questions. Its almost impressive how well they dismiss the continuous stream of calls.
http://www.youtube.com/watch?feature=player_embedded&v=bHAiB7tOeGo#t=1106