Autism Resources - Sites with Definitions of Autism

Autism at Wikipedia (A "Must Visit" site)
Autism Fact Sheet from National Institute of Mental Health.
Autism from KidsHealth
Autism Information Page at National Institute of Neurological Disorders and Stroke
Autism Primer at TEACCH
Autism Spectrum Disorders Publication (PDF) and Addendum from National Institute of Mental Health.
Autism? ...What is it? from autistics.org
Learn the signs at Centers for Disease Control and Prevention
Overview of Autism from The Center for the Study of Autism
What Is Autism? from The Autism Society of America
What is Autism? from The National Autistic Society (UK)
What is autism? from Ontario Adult Autism Research and Support Network (OAARSN)
What Is Autism? from The Autism Picture Page