My disclaimer: I am not a professional. I just like local theatre, writing plays, and reading and writing about theatre. Here are some things I have found helpful to listen to while I am at my 'real job' to keep me thinking about how to improve the script(s) I have rolling around in my head at the moment:
I have come across a wonderful podcast from Cry Havoc Company that goes through play writing, play creation, acting, direction, etc. that I have found highly enjoyable.
I haven't listened to a podcast that I haven't enjoyed from this group.
Additionally, there are many free audio editions of Pulitzer prize winning plays available on YouTube - many produced by NPR. (Here is a plug to support your local NPR station - http://kcur.org/ )
For example: "All my Sons" is on YouTube in two parts to listen to. This will give you the ability to listen to the dialogue alone and how the dialogue drives the action.
Another great video series on YouTube is The American Theatre Wing's The Characters Start Talking: all of this series is good, but of course I love the one with Annie Baker, Rinne Groff and Karen Hartman discussing play writing.