The AP has just posted a long list of upcoming specials. Many of these are repeated, so check your local listings for additional airdates. Here are few I know about:
The History Channel Sept. 11 102 Minutes That Changed America. (8:46am on both History & A&E) The current Idea Book For Educators (listing History, A&E, Bio and Lifetime programs for use in the classroom) contains a lesson plan for the History Channel documentary "102 Minutes That Changed America." (I found the doc streamed in its entirety here.) You can sign up to receive the book here. The study guide/lesson plan for the doc can be downloaded here.
Home page for 9/11 programming and other resources
NBC September 5 “Children of 9/11″ at 10 p.m September 9 DATELINE, 9:00 PM/ET September 11th, NBC News Special, 8:00 to 11:00 AM
MSNBC September 1st “Day of Destruction – Decade of War.” 9:00 PM/ET September 10 "On Native Soil" 3:00pm September 11 “9/11: In Our Own Words” 8:00 PM/ET