I and I think a few other people have been trying to find a good way to interface 8x8 common cathode rgb led matrixes with the arduino.
I made a post on my blog about the options currently available. See next post.
but I was wondering what everybody else might think about this situation. My current plan is to wait and see what the Seeed Studio Rainbowduino looks like when released. From what I can tell, the SparkFun serial connected matrix seems like it would be by far the easiest to use, as it has libraries implemented for it already... However they will not sell me the driver separately from the matrix, and I already have a matrix! It also is a bit expensive IMHO.
Thoughts? I am not quite ready to build my own driver yet, I don't think my soldering skills are good enough.
madworm and I have both produced boards that will drive 8x8 matrix parts. We both are software compatible with each other, but madworm embeds the whole microcontroller on his board while my board works as a shield.
The big downside here is that the SparkFun 8x8 matrix is not compatible. Their matrix is common cathode, which would just be a minor tweak to the software, but the pinout ordering is also wired up entirely differently, which the software itself can't fix.
If you're interested in wiring your own, I've also produced an EAGLE library that has the two kinds of 8x8 matrix, complete with pinouts and symbols.
The one from Seeedstudio is common anode row (see the datasheet http://www.seeedstudio.com/depot/datasheet/2088RGBMatrix.pdf ), and works with either board project I listed above. Their webpage mentions "common cathode" but I would trust the datasheet more. LEDsee.com's matrix is from another factory but identical pinouts.