Castroller.com is a podcast cite that one could create their own channel. Your channel could be your class discussions that your students would have the ablility to review for test material, if the student was out, they could listen to the podcast to gleen the information discussed in class that day. Cast Roller's settings allow you to limit who has access or ablility to set permissions.
I could see this being used with Art History lessons or lessons that students are working in groups with the class textbook.
