"Panic Attacks Workbook" by Dr. David Carbonell is in my opinion the best self-help book ever written for panic disorder.  It is easy to read with a great sense of humor.  I highly recommend it.  You can buy it on Amazon.com for $12.21. To order, click here: Panic Attacks Workbook

After reading Dr. Carbonell's book, I highly recommend "Mastery of Your Anxiety and Panic: Workbook" by Barlow and Craske.  The Workbook is designed to be used with a CBT therapist, but it can also be used for self-help.  It was developed by Dr. David Barlow and Dr. Michelle Craske – two of the world's leading experts in the field – and is used by many therapists around the world. To order, click here: Mastery of Your Anxiety and Panic: Workbook

You can also order "Mastery of Your Anxiety and Panic: Workbook" from the publisher, Oxford University Press, through their website:  http://www.us.oup.com/us/companion.websites/0195311353/?view=usa or by calling 1-800-445-9714. 

For more information on the Barlow and Craske approach, see: "Slowing Down and Unmasking the Panic Monster: The MAP Program"

Other recommended books:

"Overcoming Panic Disorder and Agoraphobia: Client Manual" by Elke Zuercher-White 

"The Agoraphobia Workbook" by Elke Zuercher-White and Alec Pollard

"Triumph Over Fear" by Jerilyn Ross 

"Don't Panic" by R. Reid Wilson 

 Homebound No More by Blaise Dismer

"Journey from Anxiety to Freedom" by Mani Feniger 

"Overcoming Panic, Anxiety and Phobias" by Shirley Babior 

Advice on Self-Help Groups