Canadian start-up D-Wave Systems, Inc., demonstrated the world's first Quantum Computer yesterday in the Silicon Valley in California.

This could be a big step in the evolution of computing, but D-Wave themselves is not totally convinced if it really is, as there are still many unknowns if their technology really can be scaled. Still D-Wave plans to sell the first Quantum Computer in 2008.
Quantum-computer technology can solve what is known as “NP-complete” problems. These are the problems where the sheer volume of complex data and variables prevent digital computers from achieving results in a reasonable amount of time. Such problems are associated with life sciences, biometrics, logistics, parametric database search and quantitative finance, among many other commercial and scientific areas.
More details about the Orion Quantum Computer can be found on the D-Wave site.

The Register has a very good coverage from the presentation of the Quantum Computer at the Computer History Museum.