I recently bought one of these flashy Antec cases for my Myth box, and found a lot of confusing and out of date information. So below is what I had to do to get the LCD portion of the case to work properly under Ubuntu 8.04 on an x86_64 machine.
I have not attempted to get the volume knob or the IR receiver to work, as I don't have a MCE-compatible remote control and lirc doesn't appear to easily handle multiple devices.
The appropriate device driver is lirc_imon.ko. There is one with the standard Ubuntu kernel, but it will only work with this case as of Ubuntu 8.10. With 8.10, be sure to set the is_lcd option to 0.
For versions of Ubuntu before 8.10, there is an old patch out there, but don't use that. Just download the latest CVS of lirc and build/install that.
You will first need to download all of the utilities to build lirc (apt-get build-dep lirc). You will also need to apt-get install kernel-source. Be sure to do the following steps in the kernel source:
cp /boot/config-XXXXX .config
make oldconfig; make
(You can kill the make after a minute. It just needs to set up the architecture-specific symlinks)
(in /usr/src): ln -s linux-source-XXXXX linux
Now configure the lirc source to build the imon_lcd device and type make. You don't have to do a complete install, just copy over the lirc_imon.ko in the /lib/modules/ directory, depmod, and reboot.
The Ubuntu version of lcdproc is out of date. I had to download, build, and install the latest cvs version. This is still true as of Ubuntu 8.10.
From here, I just had to enable the use of LCD proc in the frontend configuration, and I was off to the races.