There was a great five-part (1, 2, 3, 4, 5) show on the the development of written language on In Our Time with Melvyn Bragg. I found the first two episodes quite fascinating. Melvyn Bragg discusses everything from the technology of writing to the development of literature in the whole series. The first two episodes focus on writing's early evolution from an accounting system into an alphabetic system and then the development from clay to paper.
For some reason only the first two episodes downloaded into my iTunes from the In Our Time podcast, but the rest of them might be heard on the website. Enjoy!