01 buick regal brakes popping/ crunching

I have a 2001 buick regal with 90,000 miles on it. When I press the brake pedal I can feel a popping or crunching feeling. There is a slight noise that is made but you can barley hear it. I could also feel the same popping/crunching feeling in the steering wheel occasionally, but it mostly is in the brakes. I know very little about cars and was wondering if anybody knew what might be wrong. Thank you guys...