The most effective form of therapy for panic disorder is cognitive-behavioral therapy (CBT).

Here is a quote from the website of the APA, the American Psychological Association (http://www.apa.org/pubinfo/panic.html):

"How Can Panic Disorder Be Treated?

"Most specialists agree that a combination of cognitive and behavioral therapies are the best treatment for panic disorder.  Medication might also be appropriate in some cases."

More and more therapists are learning about cognitive-behavioral therapy.  However, at this time, one often has to be very assertive to find a therapist who is trained in CBT.  

Finding a Therapist: A Step-by-Step Guide

What is CBT?