I recently completed my master's degree in Educational Technology. My capstone project involved using the free program Audacity to create podcasts with students in a second grade classroom to improve their reading fluency. Not only did the children enjoy the activity, but all of those involved did improve their fluency. Here is a site I found with more great ideas for using Audacity in the classroom:
http://kerileebeasley.com/2009/04/08/10-great-ways-to-use-audacity-with-your-students/