Wiki Page - Detailed documentation about how to build and operate a CubeSat Simulator
Here are links to information about the AMSAT CubeSat Simulator
Announcement about the limited availabilty of Beta CubeSatSim Kits
Here is information about the Beta v1.3 hardware and software release of the CubeSatSim
Code - The source code for the C language software for the Simulator
Papers - AMSAT Journal articles about the CubeSat Simulator