Tapir (http://www.algy.com/anxiety/index.html) 
This is a "grassroots effort" to help people with anxiety disorders. I highly, highly recommend it. It contains tons of information, but, more importantly, it has features to allow people with anxiety disorders and caretakers to connect with other people in similar situations. There are pen-pal lists, personal story pages, message boards, etc. One of the oldest and most popular resources for people with anxiety disorders on the Internet.

Mental Help Net (http://mentalhelp.net)
Includes sections for symptoms, treatments, organizations, online resources, and research about specific mental health issues, including anxiety disorders. A big, comprehensive website, not to be missed!

Anxiety Self Help (http://www.anxietyselfhelp.com)
This website, run by a contributor to Conquering Panic and Anxiety Disorders, offers a whole range of treatment ideas--meditations, herbal remedies, traditional medicines, affirmations, books, etc.

Music Therapy: The Power of Music (http://www.enterthefreudianslip.com)
Examines the power of using popular music, something people already listen to, in therapy.  Includes examples of therapeutic messages in popular music as well as original music by Freudian Slip, therapeutic rock band.

About.com's Mental Health Website (http://mentalhealth.about.com/health/mentalhealth/mbody.htm)
Up-to-date information about a variety of anxiety disorders: articles, forums, chat, links to great resources, and a free newsletter.

International Emetophobia Society (http://www.emetophobia.org)  
A website meant to educate and desensitize people with a fear of vomiting. Includes a message board, chat, illustrations, newsletter-- and don't miss the "strange activities" list.

Anxiety Disorders - The Caregiver (http://www.pacificcoast.net/~kstrong)
Support for support people! This website is meant for caregivers, family and friends of people with anxiety disorders. Plenty of information, community, and resources.

Social Anxiety Australia (http://www.socialanxiety.com.au)
Informational website, support groups, and message board for people with social anxiety disorder in Australia.

Social Phobia Net (http://www.socialphobianet.com)
Run by an individual with social anxiety, this website includes discussion boards, chats, and accounts of other people's experiences.

Veritas Programming (http://www.sover.net/~schwcof/about2.html) 
Free or low-cost booklets and other publications about anxiety disorders, particularly PTSD.

Panic and Anxiety Hub (http://www.paems.com.au)
Lots to read here, including articles, techniques for self-help, research and studies, a bookstore, and more. Also offers one-on-one support (paid) via e-mail and chat.

PubMed (http://www.ncbi.nlm.nih.gov/PubMed)
Free, searchable database of medications and medical research.

Peer Support Network (http://www.anxietytofreedom.com)
Run by Kim Phelan, this website offers message boards, a newsletter, affirmations, a support list, and resources for people with anxiety disorders.