Here is the Attorney General's Summary of Proposition 38 (including the Legislative Analyst's summary of the fiscal effects):
SCHOOL VOUCHERS. STATE-FUNDED PRIVATE AND RELIGIOUS EDUCATION. PUBLIC SCHOOL FUNDING.
Initiative Constitutional Amendment.
Authorizes annual state payments of at least $4000 per pupil for private and religious schools phased in over four years.
Restricts state and local authority to require private schools to meet standards, including state academic requirements.
Limits future health, safety, zoning, building restrictions on private schools. Requires release of composite test scores of voucher pupils.
Permits Legislature to replace current voter-enacted constitutional funding priority for public schools (Proposition 98) with minimum formula based on national per-pupil average, as defined by terms of this measure.
Short-term (first several years) state costs averaging between zero and $1.1 billion annually.
Longer-term (within five years to ten years) net fiscal effect on state funding of K12 schools is largely unknown. Annual impact likely to range from costs of about $2 billion to savings of over $3 billion, depending on the number of pupils who shift from public schools to private schools.
Debt service savings to the state and school districts potentially in excess of $100 million annually after 10 years to 20 years, resulting from reduced need for construction of public schools.
Potential loss of federal funds in the hundreds of millions of dollars annually.