I have a light in my house that I would like to be able to turn on and off via the internet. I need to find/build some kind of switch or relay that is controlled through a serial, parallel, or USB port. The switch then of course needs to be accessible via the internet...I want to be able to turn it on and off using my cell phone. Does anybody know where I might be able to buy such a device, or find schematic for building something?