Dave Woodcock's Introduction to Organic Nomenclature is one of the course texts. It uses Java-based molecular models that are controlled by Javascript, so be sure that both Java and Javascript are enabled in your browser.
Stereochemistry Online has twenty practice problems in stereochemistry. They require MDL Chime.
A conformational analysis tutorial, from Albert Pratt at Dublin City University; this includes stuff like axial and equatorial bonds in cyclohexane. It requires MDL Chime.
The IUPAC Rules of organic nomenclature, courtesy of Advanced Chemical Development.