Anxierty Disorders Association of America
This website provides useful information about the diagnosis and treatment of panic disorder.
http://www.adaa.org/GettingHelp/AnxietyDisorders/Panicattack.asp

Yahoo Panic Support Groups
Yahoo has 93 different online support groups for people suffering from panic disorder.  Some are online chats that meet weekly and others are simply email based groups.
http://health.dir.groups.yahoo.com/dir/Health___Wellness/Support/Diseases_and_Conditions/Mental_Health_Disorders/Anxiety_Disorders/Panic_Disorder

American Psychological Asociation
This website answers some of the most common questions about the symptoms, causes and treatment of panic attacks.
http://www.apa.org/topics/anxietyqanda.html

Psychoeducation
Describes the cognitive behavioral and medication treatment options for panic disorder.
http://www.psycheducation.org/anxiety/panic/introduction.htm

Support Groups
This is a list of support groups in California for axnxiety disorders.  Itt was compiled by the Anxiety Disorders Association of America.
http://www.adaa.org/GettingHelp/Selfhelp/california.htm