Podcasting in Math

Podcasting is a unique way to share information with other through the spoken word instead of the written word.  I think podcasting could be used in a variety of classrooms but I feel that there is a limit to how many times it can be used in mathematics.  I think podcasts could be a great way for students to explain to other what they might have missed during a class period.  I believe that it is difficult to understand mathematics without visualizing how problems are solved which makes it difficult to incorporate podcasting into the curriculum.  I would be interested to find out how other math teachers are using them in their classes.  I find that it would be a beneficial way to do some professional development but other than that I find using it in mathematics it would be difficult.