Anybody who knows about auto repair should probably know this, but I do not.

I have a 2000 Mazda Protege ES:

-Over the course of a few days the car developed a progressively worse
vibration in the left front wheel. It is a high frequency vibration, and
makes a noise like a fast revving motorcycle.

-It occurs anywhere higher than 15 MPH; at higher speeds the frequency of
the vibration is so high that it seems less noticible.

-The steering wheel itself does not vibrate.

-The vibration gets worse when turning the car to the same side (left) and
goes away when turning to the (right).

-I just bought two new front tires, but the vibration persists.

I'm thinking bearings. Anyone have any other ideas?