Coursera offers a free GIS class from Penn State called Maps and the Geospatial Revolution. You can sign up and take the class. In addition to the content there is a component of interacting with other students and commenting on critical thinking type discussion boards. However, this class begins on April 30, 2014.
In the interim, you can take a look at the free class calendar and select any classes with a blue link. Once you click the links, take a look at the contents on the left hand side of the webpage.
You may be interested in:
GEOG 482: Nature of Geographic Information - This course explores the nature of geographic information. To study the nature of something is to investigate its essential characteristics and qualities. To understand the nature of the energy produced in a coal-fired power plant, you would need to study the properties, morphology, and geographic distribution of coal. By the same reasoning I believe that a good approach to understanding the information produced by GIS is to investigate the properties of geographic data and the technologies, professions and institutions that produce it.
Here is an example of the GEOG 482 landing page. If you click Chapter 1: Data and Information, there will be an onslaught of begining GIS content.