new to arduino, sound interfacing question

I apologize if this has been answered before, I have searched but have been unable to find what I am looking for. I just started working with arduino last week.

I want to have the arduino sense the dB level of a space, and use that information to control the intensity of LED lights.

I have been able to do this in regard to proximity using IR sensors, but would like to try the same with sound.

What sensor would I need to measure the volume level? I’ve looked a little on sparkfun and other websites, but I am not sure what I should use.

Thanks, any help is appreciated.