The Tribute first began back in 2002 when The Municipal Art Societey of New York ran a temporary installation from March 11 - April 14, 2002. The Tribute in Light is a total of 88 search lights that shine into the night sky that resemble the twin towers in blue light shining into the heavens. They launched it again in 2003, and it has ran every year since.
The second video that I embedded is a view from the other side of the river facing the financial district. This video was uploaded by the Associated Press youtube channel.
SOURCE: Riceman2011 on Youtube
SOURCE: Associated Press on Youtube