[Update June 2015: This method of installing CHDK is no longer useful. Use STICK.]
I added a new video to the wiki on the PLOTS visible/NIR camera tool. It has step-by-step instructions for one method of installing CHDK (Canon Hack Development Kit) on a 4GB SD card using a Windows PC. CHDK is required in order to have a timer trigger the camera shutters synchronously.
There are written guidelines at the wiki for installing CHDK on larger SD cards and for using a Mac. There are multiple ways to do these installations. If you have experiences with other permutations, adding them here or at the PLOTS Google Group forum could help others use this tool.