They are a fine resource for learning about Women's History, especially that part of the history that took place in the United States.
Check out their website for more information. While you're there you might want to Test Your Knowledge of Women's History. Sample questions include:
Who was the first African-American woman poet to have her works published?
What was the first Hispanic woman to serve as U.S. Treasurer?
Who spoke out for the advancement of of American Indians' rights from speakers platforms nationwide and before Congressional committees int eh 1880s?
What woman was invtied to teach nuclear physics at Princeton University, even though no female students were allowed to study there?
Here's the site - for more about the Project and the answers to the questions.
The National Women's History Project -