The concept is simple(ish)... send robots into space, land them on the moon, and use the moons natural resources to build a giant belt of solar panels that would beam energy back to Earth solving the worlds power problems in one single, green, swoop.
Read the article on Treehugger "Japanese Company Eyes Building 6,800 Mile Solar Array On Moon, Constructed By Robots".
Of course the technology, funds or will doesn't actually exist yet. Indeed while the idea is sound I'm not quite sure how they would get the energy back from the moon to Earth (visions of cities being microwaved by giant arrays)... and what if something went wrong; would we come to rely on the moon belt so much that the whole planet gets turned off (would we end up eating eachother?) - no, it's a great idea and one I hope gets properly considered. Dream big and who knows what we may end up with! Certainly we live in an age where I hope to see pioneering projects and journeys to space becoming the norm (e.g. space tourism). But in terms of powering our planet? I'd like to see more green power generated down on here on Earth.