On the September 25th broadcast, Science Friday will be interviewing author Kathryn Harkup about the poisons of Agatha Christie. The announcement is on their Facebook page -- it's not on their web page yet. If you can't catch the program (on the radio or on an online station stream) it should be available as a podcast pretty quickly.
Podcasts are available at their web site and Itunes.
http://www.sciencefriday.com/