alouisallen:
I posted a simple question about stepper motors before.
It helps if you include a link to the earlier Thread so we don't repeat ourselves.
When I push the button and let go, it will keep turning and stop at a random location, instead of stopping as soon as I release the button.
I suspect the problem is that the standard Stepper library blocks the Arduino until it completes the number of steps. Either get it to move one step at a time (which, of course, means that you have to control the speed yourself) or use the AccelStepper library which has a non-blocking mode.