If you have been listening to the latest episodes of The Amp Hour you have probably heard of Club Jameco. Chris from Pyroelectro has checkout it out, he purchased the 8X8X8 LED Cube to check it out. It is Arduino based and looks like a well thought of design. If you decide to give it a try it looks like you will need to set aside a large amount of time since the LEDs cube needs to be all soldered carefully by hand and the circuit board is perf-board based. I think a custom PCB would make this kit quite a bit better.