Squeaking from front end between 30-50mph

I've recently noticed a squeaking sound coming from the driver-side front end of the car. Strangely, it's only audible between 30-50mph. Anything lower or higher and there's no sound. If I turn the wheel to the left, the sound's gone. If I turn the wheel to the right, the sounds still there. It gets a little louder the faster I go. If I get on the brakes, the sound is gone. It's not a continuous squeal; it's more of a squeak-squeak-squeak-squeak (maybe 4 squeaks per second?). It's loud enough to be heard with the windows up, and it only happens after about 20 minutes of driving.

Anyone have any ideas on what this could be?