I was at work when it happened, and chatting with a friend in California at the time (who obviously wasn't sleeping well (I lived in EST) - it was early) and I got a page from a friend (wow, 10 years ago we were using pagers!) and a quick back to my Yahoo home page or whatever and saw the first plane ... and then the second one ... and inbetween I'm telling my friend "Turn on the TV now!" Because since I was at work I couldn't see what was going on so I had her on the phone and we were talking back & forth and it was pretty weird.
Ofc, you need to realize I also remember the day that NIxon resigned, and the day that Elvis died and the Challenger exploded... I remember where I was and what I was doing during all of those too.
But still, it's a bit hard to believe it's ten years now.