Learn More... Basic Superconductivity
A good introduction to the topic of superconductivity can be found on the Wikipedia page:
WIKIPEDIA: SUPERCONDUCTIVITY
Some useful and fun images from the field of Superconductivity

The Meissner effect in a superconducting sample.
All Magnetic flux is expelled below Tc in a Type I superconductor

Magnetisation properties of Type I and Type II superconductors

A standard representation of the perovskite crystal structure of the superconductor YBCO

The goldfish (complete with magnetic bowl) is levitated above a base of superconducting
material by cooling the superconductor below Tc. Note no animals were harmed in this experiment!