Additonal resources...

The Anxiety Release Method is the 'NEW' and improved updated version of Panic Away.  The only real difference is Joe Barry (creator of Panic Away) has some great bonuses included and there is an excellent forum to share your experiences and meet people who have also experienced panic attacks.

The Linden Method.
I do not have any personal experience with this method, however, their site and the information is very thorough.

Article: Causes of Panic Attacks

Article: Eliminate Panic and Anxiety Attacks for Good