I was at work in Belleville NJ, and first heard about it from a friend who was driving into work on the NJ turnpike. He yelled 'a jet just flew into the twin towers!' I ran up to the roof and saw the second plane hit. Saw the towers fall, and then came back inside and started telling everyone to go home. The plant receptionist was hysterical. Her niece's fiance worked at Cantor Fitzgerald, and they had just found out he probably didn't make it out. The niece was on the phone with him, and the phone had cut out.
A family friend was the chief nurse for Merrill Lynch, and her and five other nurses were at the base of the towers helping burn victims as they came out. All these years later she still gets nightmares about the sound a human body makes when it hits pavement (it's a 'pop' not a 'thud'). The cops grabbed her as the first tower fell, and she made it out. President Bush gave her a presidential citation at a White House reception for her a year or so later.
I got home, looked up, and saw F-15's flying CAP over the NYC area, clockwise. Will never forget it.