In essense, state funded 'faith schools' are against the constitution.
When it comes to 'faith' schools in the united states, there are a number of private schools that are run by various religions. There are some very good schools that are run by the Roman Catholic church. I don't beleive all 'faith'schools are equal, or even all the schools run by the RCC for that matter.
There is an ongoing debate about the use of 'school vouchers' and letting people use that for sending kids to 'faith based' schools.