We should hold students accountable at the stations so that they can obtain the full benefits of using the stations. If they aren't accountable then sooner or later the stations will not be useful due to them being destroyed or the fact that they aren't staying on task because of a lack of accountability.
Coaches' Eye and Animoto would be two applications that I could use in which the camera on the iPad/iPod could help me capture the way students move and display it to them.
Student's could use Coaches' Eye to capture their partner moving while working on form running. Then they could talk about the proper mechanics of form running and record them again. They could display the assignment in Animoto so that they can compare and contrast the differences.
I could also use the iPad to get quick breakdowns of technique issues during my volleyball practices. Then I can have immediate feedback to show players when their technique is slipping.