Indiana Governor Mitch Daniels has signed the nation's most sweeping private school voucher program into law.The program directs taxpayer money to private and religious schools. It's based on a sliding income scale. Families of four that make more than $60,000 will qualify for a scholarship if they move from public to private schools.Critics say the plan will spread education funds too thin and give federal money to religious schools.In addition to signing the voucher bill, Daniels also signed legislation aimed at expanded charter schools, which are publicly funded but free of many state regulations.Additional information from the Associated Press