Hi
The method I would use is a gameport plugin. There is one here that can be used on its own.
http://www.cocoontech.com/index.php?showtopic=228
http://www.gadgetjunkie.net/index.php used to have a page describing how to wire the gameport for inputs. You would need to use a relay switched by the doorbell not just connect the doorbell to the gameport.
You would then want to use this to control the volume. I have somewhere a small program call setvol. It controls the windows master volume.
Maybe this
http://www.pcworld.com/downloads/file_d ... 480,00.asp would be easier.
You could set up a button on xlobby to unmute.
The x10 route would work but would cost a lot, powerflash & pc interface would proberbly be £50 compared to using the gameport which may cost £5
Sorry this post is a bit rushed but I am going out but I thought you might like some info to look into
Tim