as I was asked at Twitter, I wanted to let you know how I managed to get a 20x4 character lcd to work with the Raspberry Pi.
First of all, it's a display with a HD44780 controller, so originally designed for the lpt port. There exists a open-source project named lcd2usb at
to connect these displays via USB.
From lcdmodkit you can buy displays complete with an lcd2usb adapter ready for USB, as I did.
The displays come with an internal USB connector. Because the Raspberry Pi does not have internal USB ports on it's board, I cut a standard USB cable open and soldered the four wires together. That was the only hardware modification I had to do.
XBMC has support (only) for lcdproc. From this point, there is no difference in installing and configuring lcdproc for a normal linux pc.
If you have further questions ask them, I could provide the config files, but there is no magic.