Over the weekend I stumbled across a great wiki dedicated to the use of VoiceThread in education. The wiki is appropriately titled, How to Make a VoiceThread. On How to Make a VoiceThread you will not only find directions for using VoiceThread, but also examples of VoiceThread being used in education.
http://www.freetech4teachers.com/2010/01/great-wiki-how-to-make-voicethread.html