The Wikipedia page for c-squares, https://en.wikipedia.org/wiki/C-squares has received a substantial update as at April 2020. See this page for the system description, rationale, and a moderately extensive list of references.
Courtesy of Mike Fuller of CSIRO Australia (ESRI GIS user), we are now able to post a set of shape files for c-squares at a range of resolution, available for download - look for the folder "shapefiles" in the "Files" area.
Patch uploaded for C-squares mapper version 3.0 (small file that was omitted from master zip file) - see "Files" section
The source code for the c-squares mapper V3.0 has been posted in the "files" section. This is the current release as at 15 June 2006. A working installation of the latest release can be accessed via the "quick start" entry point at http://www.marine.csiro.au/csquares/about-mapper.htm .