The cypress_m8 module started being distributed with linux kernels 2.6.10 and above. The instructions originally here have since forth been deprecated. This is only for people wishing to use the Earthmate with the USB interface. As mentioned here and elsewhere, the device can be connected via a standard rs232 serial interface.
To enable the driver, from menuconfig or xconfig select:
Device Drivers->USB Support->USB Serial Converter support->
<M> USB Cypress M8 USB Serial Driver (as either built in or module)
Compile, install, then reboot. Depending on your distro, the node being created by the driver can show up as /dev/tts/USB0, /dev/ttyUSB0, or /dev/usb/tts/0 (the number will vary). If you have udev, you can configure it to create the node however you like based on the product and vendor ids; VID:0x1163, PID:0x0100. Check with your distro for support on where usbserial nodes can be found and for further information on configuring udev.
For people not using linux or using a kernel less than 2.6.10 or even the 2.4 series, please check out the emul project at:
http://developer.berlios.de/projects/emul