An extensive list of other GIS sites on the World Wide Web is maintained by Harvard Design and Mapping. This list includes data sources, GIS software developers/vendors, discussion groups, project sites, and more.
Another extensive list of GIS sites is maintained at Kingston University, United Kingdom.
Request for suggestions/enhancements. We're not lonely (we get over 1 million Web-hits per year). So don't feel an obligation to email us. However, if you have candidates for enhancements to this short course, or if (horrors!) you find something to correct, please let us know.