Headaches 
Defines the different types such as tension and magraine. Includes the causes, symptoms, and treatment of each.
http://www.headachecure.org/
Migraine prevention and treatment resource directory. Includes articles and info on homemade migraine treatments, triptans, and the causes of migraines.
http://www.migraineguide.com/
Articles about migraines, personal migraine stories, migraine news, and a weblog about migraines.
http://www.migraine-notes.com/