The national Twins Club. The Pennsylvania Twins Club. Twins Magazine Lots of great information from a magazine devoted to twins.
Parents Place Another good site with lots of parenting information.
The Twins Foundation A research information center on twins and other multiples. PotatoNet Parents of Twins and Triplets Online. Twinslist.org Find information on mailing lists and discussion groups relating to twins. Twins Days Information on the Twins Days Festival in Twinsburg Ohio. Twin Stuff A commercial site aimed at items of interest to twins and parents of twins.