A great place to start is New Scientist magazine’s guide to the Quantum World:

CQT has its own quantum briefing room:

Here’s “Quantum Computing 101″ from the Institute for Quantum Computing in Waterloo, Canada:

CQT’s director, Artur Ekert, on quantum cryptography

A poster on what quantum computing is all about:

Science writer John Gribbin offers his take on some quantum mysteries:

New York Times writer John Markoff discusses the emergence of quantum computing:

Vlatko Vedral asks if we can find those pesky parallel universes:

Here’s a slightly more technical introduction (warning: equations ahead!) with links to pages that deal with all the main aspects of quantum theory:

Another general look at the theory

A lovely introduction to the spooky phenomenon that is quantum entanglement:

and here’s a look at superposition: