The LCSIM Software used by SiD is documented on the
ILC node of the SLAC Confluence Wiki
As the University of Bristol group starts its SiD analysis effort, they are making notes which should be useful to any person or group starting out:
SiD node of the University of Bristol Confluence Wiki
SiD Spokesman Marcel Stanitsky maintains a How To Guide for Installing and running SiD and ILC software packages