If you only hear or feel the noise when the car is moving, the problem can be either on the tires, wheel assembly or the transmission.
Check the tires for signs of uneven wear (faulty alignment); then check rotors and brake pads for signs of grease or oil contamination.
Raise one of the front tires and grasp the top and bottom of the tire; then try wobbling the wheel and tire back and forth; you should notice very little wobble or nothing; otherwise, the wheel bearings are worn or damaged. Repeat the test on the other front tire.
If the problem just started and you can't find the source of the problem, you might want to have the alignment checked before it gets worst and you need to replace the tires.