Phone Calls Mutes Computer Speaker via Bluetooth

Does anyone know if OS X has an option or an app that I can get (for free) that will mute the speakers of my computer, or even pause iTunes when I receive a call on my phone.

I listen to music kind of loud and my phone has a vibrate that would lull a baby to sleep.

I imagine this is possible via bluetooth and I though I have heard of this before.

Thank you!

Not sure if it can pause the music, but this lets you control itunes from your phone.

Signal - The Ultimate Media Player Remote