Learning Mathematics using only audio.

I can't really point to a source, but I find the question quite relevant, as audiobooks of mathematic subject can be important also for blind people.

Learnoutloud has a repository of audiobooks and podcast about math and statistics, and related novels as well. Nevertheless it seems to offer no advanced math repository.

PapersOutLoud may be a good project.

My suggestion would be to narrow down topics you would like to learn and find YouTube videos of them, then download those YouTube videos listen to them during your commute. I have a daily two hour bus commute and use youtube video's audio to reinforce topics i'm learning at school.

For example: Lets say you want to review calculus, listen to this video on repeat for an hour (its 20 minutes long so you could get through it 3 times!) http://www.youtube.com/watch?v=di_bzYD0Mkg