Below is a list of audio or radio dramatizations dealing with topics in the post-apocalyptic genre (including zombies).

Title Type Description
The War of the Worlds Audio Drama The grand-daddy of all post-apocalyptic radio dramas. (Ok, I guess it’s more apocalyptic than post-) Definitely worth a re-listen.
For civilization to survive, the human race has to remain civilized. The Shelter (The Twilight Zone)