If you didn't have your rotors turned when you replaced your pads, you could de-glaze your rotors with an abrasive pad attached to a grinder or drill - the techs at the dealership I used to work at would do this when a customer was having brake squealing issues. All you're trying to do is roughen up the surface, not to take off any significant amount of material off or put any deep scratches in it, so don't use anything too coarse. It's easiest to do it with the rotors off the vehicle but if you have a small enough pad you can just pull the caliper out of the way to access the back side. Make sure you have all the anti-squeal shims in place on the backs of the pads also, they really do work.