I recently found a really nice FREE animation of the action potential. It's from Harvard's outreach program and it does a great job of breaking down the essential processes of this hard-to-learn, hard-to-teach concept.
I've just added it to my own course outline so that my students can access it easily. One might also use it during class, or a tutoring session with students, to reinforce understanding of the action potential's mechanisms. Hmmm . . . this could also be a good thing to go through with my students in my A&P 1 Supplement course, eh?
Action Potential Animation
Action Potential Video
[Another nice, animated explanation of the action potential]
Action Potential Diagram
[A free diagram of the action potential. Compares the ideal "schematic" to a recorded action potential.]