University of Utah
University of Utah: Cardiovascular Pathology Index
This site features a detailed index of photographs for cardiovascular pathology. You can see what a normal human heart looks like and what a sick one looks like too. Come and check it out.
PBS
Nova Online: Map of the Human Heart
This PBS site has a concise explanation of how the heart works. There is also a moving diagram of a working heart.
Treehut
Suzy's World: Heart
Find out why your heart beats and perform an experiment to see your pulse moving.