NerdKits Multi-Panel LED Array using SPI
Here is a good video about communicating amongst multiple microcontrollers. In this case they are NerdKits that are distributing sign data so that a huge Multi-Panel LED Array can be built. Even if you aren’t interested in the project have a look at it for the SPI info. “In this project, we put a new twist on our old idea, and modified the LED Array into a giant multi panel