"A friendly introduction to quantum error correction." Try it!
"A tutorial on quantum error correction," A. M. Steane, Proceedings of the International School of Physics ``Enrico Fermi", course CLXII, ``Quantum Computers, Algorithms and Chaos'', G. Casati, D. L. Shepelyansky and P. Zoller, eds., pp. 1--32 (IOS Press, Amsterdam 2006). Arxiv pre-print, quant-ph/.
3 lectures on quantum error correction. This is a pdf file containing visual material for a set of 3 lectures introducing quantum error correction. It could be used in conjunction with the above tutorial article.
3 bit QEC example.[Warning: large file, 2 Mbyte]. The first (3 bit) example in the tutorial is worked through in this (web-converted) powerpoint presentation (very basic level, final year undergraduate or early graduate).
QEC, stabilizers and code construction.[Warning: large file, 1.7 Mbyte]. This is a brief powerpoint presentation of QEC ideas at a more advanced level. It can also be used in conjunction with the above. (graduate level).
Fault tolerance.[Warning: large file, 5.7 Mbyte]. This is a powerpoint presentation of the main ideas of fault-tolerance. (graduate level).