A Guide to Superconductivity: http://www.physnet.uni-hamburg.de/home/vms/reimer/htc/contents.html
Introduction: Superconductivity Basics: http://supercon.lbl.gov/MCoccoli/Files/Supercon/Thesis/ThesisBook/Chapters/Introduction.pdf
Materials by Design: Superconductors: http://www.mse.cornell.edu/courses/engri111//superco.htm
Superconductivity Basics: http://www.americanmagnetics.com/tutorial/basics.html
Superconductivity Concepts:http://hyperphysics.phy-astr.gsu.edu/hbase/solids/supcon.html
Superconductor Links: http://superconductors.org/Links.htm
Superconductor Uses: http://superconductors.org/Uses.htm
The Physics of Superconductivity: http://www.physics.uoguelph.ca/nicol/supercond/resources.html