[Asperger's Disorder Home Page (US)] - summary here.

[Autism in the UK (SFTAH)] - summary here.

[Autism Related Resources on the Internet] - summary here.

[Autism Resources] - summary here.

[Autism Spectrum] - summary here.

[Exploring the Savant Syndrome (US)] - summary here.

[International Rett Syndrome Association] - summary here.

[IPWSO - International Prader-Willi Syndrome Organisation (DK)] - summary here.

[Jypsy's (hundreds of) Links (US)] - summary here.

[National Autistic Society] - summary here.

[Prader-Willi Syndrome Association (UK)] - summary here.

[Williams Syndrome] - summary here.

[World of Autism] - summary here.