I recently obtained an 8 by 8 three color RGB LED array to play with. I set it up with three 74595 shift registers and an arduino. It was really easy to get it working. Here is a link to the company that sells the LED array.
Here is the video of it working on youtube:
I might eventually post the code but it follows my code that was used for the two color 8x8 arrays that is found in my book "Arduino LED Projects".
Here is a blue smiley face (with white hair) using the RGB array:
Here is a red, green, and blue flag using the RGB array:
I am contemplating making a larger RGB sign so I can do scrolling text in full color.
This is the schematic diagram: