Tutorials and introductions to GIS can be found on the web. GIS.com (another site from
ESRI) offers a very nice introduction, including explanations of GIS,
geographical and cartographical concepts, and links to live data, data
for download, and more information.
Also, try a general web search for gis tutorials and limit to
educational instututions. For example, in Google, type:
"gis tutorial" site:.edu
The GIS community is an active one and there are many listservs and
blogs to which you can subscribe, for example, Free GIS Data &
Imagery GeoBlog.