The internet can be a great place to access information, but it can also be a place for mis-information. I am a believer in going right to the source for information.  The organizations managed by Marsha Linehan (the developer of DBT) and the individuals she has trained are great, reliable sources of information. Below are some of the websites, organizations, and materials I often recommend to my clients and to clinicians interested in getting trained to practice DBT because I have found them to be useful and credible resources.  

"I believe that the solution has to be the development of a theory that is based on sound scientific principles, highlighting the basis of the disordered "borderline" behaviors in "normal" responses to dysfunctional biological, psychological, and environmental events.  It is by making these individuals different in principle from ourselves that we can demean them.  And perhaps, at times, we demean them to make them different.  Once we see, however, that the principles of behavior influencing normal behavior (including our own) are the same principles influencing borderline behavior, we will more easily empathize and respond compassionately to the difficulties they present us with."

-Marsha M. Linehan, from Cognitive-Behavioral Treatment of Borderline Personality Disorder