PBS
Pbs Learning Media: The Leaning Tower: Where It Stands Today
Will the Leaning Tower of Pisa give way to gravity? In this interview from the NOVA Web site, engineer John Burland relates the difficult job of saving the tower.
NASA
Nasa: The Way Things Fall
This site from NASA compares free falling motion to falling with air resistance. Discusses Galileo's experiment. Explains why we believe all objects free fall with the same acceleration.