The National Service GI Bill Act This bill requires in-state tuition for certain volunteers, revises the requirements to receive certain national service grants, and revises AmeriCorps educational awards. It also requires certain grant programs to educate students about the U.S. Constitution. Specifically, states must charge in-state tuition rates for institutions of higher education to volunteers who have served in a national service position (i.e., AmeriCorps) for one year, as well as for their spouses and children. Additionally, states and subdivisions must submit a plan to the Corporation for National and Community Service to receive certain grants. Such a plan must (1) ensure that students are notified of and encouraged to commit to a term of service in the military, a national service program, or a public service job; (2) ensure that students are provided information about these options; and (3) include assurances that it will request each high school student to indicate a preference for a program and to register their intent to serve in the program. It revises AmeriCorps educational awards by (1) increasing the amount of such awards, and (2) modifying the requirements for calculating taxable income to exclude from gross income such awards. Further, AmeriCorps volunteers are eligible for appointment in the competitive service. (Currently, Peace Corps volunteers are eligible for such an appointment.) Finally, national activities supported by American History and Civics Education grants must include programs that educate students about the history and principles of the U.S. Constitution, including the Bill of Rights.