Oddly enough, one of the best sources for information about the schools and school rankings is a local real estate agent (i.e. estate agent), particularly one from one of the larger national chains of agencies - like Century 21, Better Homes and Gardens, Coldwell Banker, etc. This information affects home values, so it's important information for those trying to sell homes.

It's also the case that real estate agencies handle rental properties (and normally don't charge a fee to the renter - though in the NYC area this is different, check for a "no fee" agency). Talk to a few different real estate agencies, or check their websites - they often make the comparative school information available online.
Cheers,
Bev