Plays are much different than movies, as they generally go un-edited for reasons that film would frequent: time, content, necessity of line...
Most major plays have been filmed, and many less know ones as well.
The first thing I recommend you doing is searching "youtube" for them, as many high school and college productions can be found there, usually in parts.
There are also many community theatre groups in most areas where you can see the plays for a small fee or for free. Nothing better then live stage action.