This is a national organization for child and adolescent psychiatry that has a page of resources for families on topics like typical development as well as disorders such as autism and ADHD.
This is a government agency and resource on children.
LD OnLine 
This is an online resource of information on learning disorders and ADHD provided by a television station in Seattle WA.
This is an informational website on ADHD provided by the CHADD organization which is partially funded by the center for disease control and prevention.
This is national non-profit organization concerning learning disorders and support for parents of children with learning disorders developed by parents of children with learning disorders
This is a website in Arizona that is designed to help parents learn about disabilities and contains links to a number useful websites about different disabilities. This site also explains the Americans With Disabilities Act.