I still remember sitting at my desk in my office at the old Emery Worldwide that day. I wasn't really much of a business traveler yet at the time, but our old operations manager stuck his head in my door and said "hey, did you see a plane hit the world trade center?" My first response was "was it one of ours?" We had, just the year before, lost a plane in an accident in Sacramento.
Jumped on CNN.com, started to get a picture of what was going on. We turned on the TV and nobody got any work done the rest of the day. My first wife worked at a Navy Base. I told her to get her butt home. She eventually did, and she was off for 2-3 days afterwards while they got security lined up (she was a civilian working for the DoD). Was a crazy several days it was for us whose jobs were impacted directly by the event, although not nearly so much as many others.