The Nineteenth Amendment stated that no state can deny the right to vote based on gender. Controversy came up about the 14th amendment and whether or not it should apply to women as well. The time in which women fought for their rights was called Women's Suffrage. On January 9, 1918, the president at the time, Woodrow Wilson, announced his support of the amendment. It was proposed on June 4, 1919 and ratified on August 18, 1920.(information found at Wikihistoria )
I've found numerous places on the net that can tell you all about the 19th amendment and those who fought for it.
Washington Post's article on 19th Amendment Anniversary
Actual copy of the 19th Amendment with information
Women's History/Suffrage at About.com
But my fave piece of educational material is the School House Rock video from their America Rock series. Check out Sufferin' 'til Suffrage at the end of this blog.