1. Noise coming from rear? When was the last time you had the rear rotors changed? Look for rust on the e-brake rotor surface. Over time, water/road spray can get into the vent holes corroding the surface, forcing the rust build up against the shoes.
2. Noise coming from front? Could be power steering trouble. The belt/pulley can rub against the subframe when making a turn. Have you hit any massive potholes or bumps lately?
"That's highly significant!"