We got a couple of LED matrices in our Hackerspace /dev/tal in Wuppertal. Here there is held code and other useful things for them.
Important info: The Fusebit for "JTAG" MUST be deactivated for usage of PORT C, which is used by default for serial data!
To build the Firmware, just enter the directory "main" and type make. For flashing the firmware make flash can be used, or the main.hex file can be flashed using an arbitrary AVR flashing tool.