http://library.med.utah.edu/kw/pharm/hyper_heart1.html This is a nicely made simulation showing how blood flows through the heart and how the heart muscle contracts. The simulation can be paused, so that students can study what is happening at any particular moment.

http://www.blaufuss.org/ This site contains several excellent heart simulations and many of them include heart sounds. This one: Physiological splitting of the second heart sound in particular includes respiration, a moving heart and heart sounds. It even includes a quiz.