This is widely known as "The Last Lecture" by Dr. Randy Pausch, the Carnegie Mellon University computer science professor who is dying of pancreatic cancer. He's only 48.
The lecture is 76 minutes long, so make a date with it and be prepared to be riveted and to enjoy a wonderful life experience.
This man talks about life. He talks exceptionally well, about life.
As of 4/28/08 he is still alive and doing his best.
http://www.youtube.com/watch?v=ji5_MqicxSo