The National Alliance on Mental Health (NAMI) is an organization dedicated to educating people about mental illness and helping people with mental illness and their families. It's a great organization and their site has lots of information and resources. They even mention PMDD a little -- just a little.
And while you're at it, ask them to add more information and resources specific to PMDD
And while you're at it, ask them to add more information and resources specific to PMDD