Find photographs of the WTC, Pentagon, Flight 93 crash site and more at these links.
Seeing the Horror - Photo galleries and video interviews compiled by The Digital Journalist and American Photo. Primarily, though not exclusively oriented to the WTC
FEMA Photo Library - FEMA workers took many photos at Ground Zero, and the Pentagon, and many are available here in a searchable database (search on Disaster Number 1391 for the WTC, 1392 for the Pentagon).
Aerial shots - notable for an enormous aerial shot of Ground Zero on 12th September, but there are two or three Pentagon pictures as well
Satellite images - Just a few photographs of the aftermath of the attacks, but they’re good quality and very high resolution. See more of the same at Space Imaging.
Corbis -- Photo agency intended for use by media professionals wanting stock photographs, but you can browse it too. (You’ll be restricted to preview photo size, but it’s not bad). Search on keywords like WTC, WTC Collapse, Shanksville, Flight 77 etc for photos
US Attack Media Archive - Categorised thumbnail galleries of WTC and Pentagon shots, diagrams and more. Nicely done, although most of the photos are fairly low resolution.
Bearing witness to history - Various 9/11-related photos, including some of debris fragments and small objects recovered from the various sites
911 Digital Archive -- all kinds of 9/11-related images, audio and video files, but be prepared to search for a while. Most are related to the aftermath, personal views and so on.
CNN clips -- small images and assorted CNN clips from their September 11th coverage. Generally lo-res, but if you must have every video there is then maybe something here will interest you
Archived front pages - 110 front pages from the September 12th 2001 edition of major newspapers, showing how they covered the attacks
World Trade Centre
Here Is New York - Excellent gallery of WTC images, categorised into different groups for ease of viewing (pre-911, damage, collapse, ground zero etc).
Shattered - Time Magazine have a photo essay based on James Nachtwey's mainly post-collapse WTC shots
MediaEater - library of fairly high resolution photos showing the burning towers (no collapse images)
New York Disaster - Burning towers and collapse shots. Taken from a distance but may be useful to someone.
Early shots - A group of medium resolution images taken on 13th September 2001, so capturing the very early stages of the cleanup.
Ground Zero - 72 photos taken around the WTC on the 3rd October 2001. Decent resolution but no thumbnails, unfortunately, just brief text descriptions.
More Ground Zero - 32 shots taken around the WTC debris on 31st October 2001. Thumbnails are available, but the final resolution is a little low.
Aman Zafar - A series of pictures of the towers, taken from after the second impact, and including multiple shots of both collapses. Lots of images, but taken from Jersey City so don't expect close-ups.
WTC Damage Assessment - shots showing the damage caused by the collapse of the towers, from inside surrounding buildings. Not that interesting to most people, probably. It’s a Powerpoint presentation, too, so you must have Powerpoint or a suitable viewer installed to see the pictures.
WTC Fresh Kills Investigative Site - These 23 photos were taken by Cryptome on January 25, 2002, and show aerial views from a helicopter of the World Trade Center site, the dock used for barges to transport removed WTC debris to the Fresh Kills Landfill about 10 miles south of Manhattan, and views of the 170-acre WTC criminal investigation site
Overview of Damage to Buildings Near Ground Zero - Interesting document produced by the Multidisciplinary Centre for Earthquake Engineering Research, showing damage caused by the collapses of WTC1, 2 and 7.
PentagonResearch - Probably the best collection of Pentagon debris and other pictures.
Steve Riskus - A collection of photos taken moments after the Pentagon was hit
Security camera footage - Photos obtained by CNN apparently show the fireball resulting from the Pentagon impact
Seconds from Disaster - Still images and video clips from National Geographic Channel's Seconds From Disaster episode, "Pentagon 9-11".
US Defence Department - Photos of the Pentagon crash aftermath
Defence Visual Information Centre - Another US Government site. Search on keywords like American Airlines to get Pentagon photos
Pentagon Renovation Project - Official Government site with pics from the initial fires onwwards. Now only available on archive.org, so very slow to load.
Shanksville crash site and memorial - Flight 93-related photos. Nothing close up, but one or two of debris fragments.
Mark Stahl - A couple of relatively close shots of the Flight 93 crash scene
OpenSourceVideo - a slightly odd project where CNN, Fox, Naudet and Booker Elementary footage play in a 4-way split screen, in chronological order. The full-length version is 44 minutes long, which makes for a large file (200MB+), and the split-screen means everything is scaled down a little, more an arty project than anything else perhaps, but someone might like it.
Brainstorms and Raves Attack on America - Links to photos and videos on other sites.