how to get educational books for school purpose

Dear Forum,

as a board member of an international school , i am very interested to know if their are original study books for math, physics etc for elementary school, junior high and high school.

I have seen the new iPad for educational purpose and that looks un excellent opportunity to restructure our educational program but i would like to see that we also can provide our students with the learning materials which are the standards at US schools

thanks so much if you can help me