The Oxford Centre for Quantum ComputationThis summer I am studying quantum mechanics, particularly the areas of quantum computing and decoherence. Since, as a rising junior, I have had only a minimal introduction to formal quantum theory, much of this summer has been spent learning the fundamentals of quantum mechanics. While we have not been exploring many different problems and systems, emphasis has been on the fundamental mathematical and physical structure of the theory.
The Oxford Centre for Quantum ComputationThis is a good "home base" site, with a few introductory tutorials, links to other Quantum Information sites, job postings, and more.
A private company whose goal is "to perform research and development on the exploitation of quantum information technology." Still in the early stages, but I am glad to see more avenues of research opening up.
This site has a very good overview of many aspects of quantum computing and quantum information. The main Starlab page is also interesting.