Anyone else experience a weird noise when braking?
 

2008 3.0si with about 40,000 miles on it. The last few days I've been noticing a noise when i roll to a complete stop at a light or stop sign. The moment the car comes to a complete stop there is what almost sounds like a servo noise coming from under the car on the right hand side. It's not super loud and can only be heard with the stereo is off. I have no idea if it's something that has always been there, and I just noticed it, or if it is a potential problem.

Any ideas?