American and Japanese scientists say that the manufacturing techniques and materials for building a space elevator should be ready around 2020 or so. Currently, the stronget material available - carbon nanotubes - have only about a quarter of the strength needed.
Japan, unlike the United States, is prepared to spend $10 billion to develop the technology. A space elevator would reduce the cost of putting an object in orbit to just the electricity needed to climb the elevator. Electricity is much cheaper than rocket fuel.