American Thyroid Association
The ATA is the leading organization focused on thyroid biology and the prevention and treatment of thyroid disorders through excellence and innovation in research, clinical care, education, and public health. The site is bilingual, has useful links and allows for news feeds to your desktop.
Medline Plus
A service of the National Institutes of Health and the National Library of Medicine. Contains a wealth of information about the thyroid gland, diseases and management.