Over the weekend, I had a guest post over at FreewareGenius that covered some of the free applications that Esri provides for interacting with GIS maps and data. Go check it out if you’d like to learn about ArcGIS Explorer Desktop and some sources for GIS data.
Freeware to Get Started With GIS and Explore Mapped Data on FreewareGenius.
There are also suggestions for additional free and open-source GIS tools in the comments that are worth checking out.