Arduino control for a hi fi amplifier

Hi all, Im new to arduino projects and have never used one before. I have experience in building amplifiers however and am starting a new project possibly using the K12M tube amp kit. What I want to do ideally is to create a control unit with possible lcd graphic user interface to control the volume output of the amp. Anyone have any ideas? the amp schematic is below

I don't see any schematic.

What sort of device will you use for the user to input volume changes, and output does the Arduino need to provide to the amp to set the volume?

Sorry here is a link to the photo http://diyaudioprojects.com/Gallery/displayimage.php?pos=-99 the design is fairly basic in itself. Using digital potentiometers to control the overall gain by sending serial signals to adjust the gain. there will be several issues. Has anyone tried something similar? And could the arduino be used in conjunction with a digital pot?

It's possible for an Arduino to control a digital pot.