Here is a list of websites you may find helpful:

Multiples of America – also known as the National Organization of Mothers of Twins Club

Sidelines – information about high-risk pregnancies

Twin to Twin Transfusion Syndrome Foundation

Center for the Study of Multiple Births

Twins Magazine

Mothers of SuperTwins (MOST)

Twins List – a list of twin-related resources from around the world

Dad’s Guide to Twins

Consumer Product Safety Commission (CPSC)