Dr. Giovanni De Domenico has written some interesting articles on electrotherapy for MedFaxx.  He also is in process of creating online education materials with PowerPoint and mp3 audio for the following:
  
-    ‘A      Healthy Body is an Electric Soup’ 
 -   Electrophysical      Agents:  What are they  and what are they  used for ? 
 -   A      brief History of Electrotherapy 
 -    Basic      Concepts in Electrotherapy 
 -    ‘Sensory’      Stimulation 
 -    ‘Painful’       Stimulation 
 -    ‘Motor’      (muscle) Stimulation 
 -    Traditional      ‘Low Frequency’ Currents 
 -    Medium      Frequency Currents 
 -    Interferential      Therapy -   History and Basic Concepts 
 -    Interferential      Therapy -   Methods of Application 
 -    Interferential      Therapy -   Management of Acute Pain 
 -    Interferential      Therapy -   Management of Chronic Pain 
 - Interferential Therapy - Muscle stimulation
 
You can find more about your specific diagnosis by using Dr. DeDomenico's blog, AskDrGion.