Most national grants for teaching are open to both men and women, but they are nevertheless a good place to start your grant search. Foremost is the Pell Grant, a program of the U.S. government. Pell Grants are not specific to field of education but are based on need. You will have to fill out the Free Application for Federal Student Aid in order to be eligible for a Pell Grant.
If you are interested specifically in Montessori teaching, you can apply for the American Montessori Society's Teacher Education Scholarship. The scholarship is open to anyone who, according to the AMS, "has been accepted or is in the process of acceptance by an affiliated AMS teacher education program."
The Straightforward Media Teacher Scholarship Program issues grants four times a year to anyone wanting to teach at any level. There is also the NAACP Lillian and Samuel Sutton Education Scholarship, which awards between $1000 and $2000 dollars a year to minority students getting either an undergraduate or graduate degree in education.
The Goizueta Scholarship in Atlanta, GA is specifically targeted to Hispanic students in need who have shown superior academic ability and performance. Though strictly not only for women, College Scholarships.Org says it is "outstanding in its intent to offer Hispanic women students a fully funded tuition."
The American Association of Retired People (AARP) offers a grant each year for women in need over the age of 40 who are trying to obtain additional education. They are particularly willing to help you if you are returning to the workforce, are underemployed or are helping to raise children of another family member. The Jeannete Rankin Foundation offers grants to women over the age of 35 who are pursuing a bachelor's degree.
Individual states and colleges offer many of their own grants and scholarships for women educators. Be sure to contact colleges and universities you are interested in and ask about any available financial aid for women pursuing a teaching degree.