CallerList is a call screening application used by The Atheist Experience, a public access TV show in Austin, TX. The original concept and implementation was by Linda Raymond of Houston, TX. I rewrote CallerList so that it would be AJAX based instead of post/form based. I'm now the maintainer of CallerList. CallerList has a GitHub page here.
It's possible that there will never be any interest in this application outside of ACA, but in any case you can download it here