Audacity is a free recording program that we have started using in our lessons. The software shows you what your sound looks like and can play it back for you. Watch the video below for a little tutorial I created on how to use it at home. You may download it at: http://audacity.sourceforge.net . If you scroll a bit further, you'll see a video on how I use it in lessons.
The video below is an example of how I use Audacity in my lessons. The lesson below is a fifth grade clarinet lesson from Cayuga Heights.