As part of the government's Vision for Space Exploration (VSE), NASA had proposed to create a new launch system called Orion to enter use by 2015 as part of the Constellation program. Whatever you may think of Orion (and there are plenty of detractors) this is the launch system that—for better or worse—NASA will be using post-shuttle. With the space shuttle retiring in 2010 (or 2011, depending on Congressional priorities and willingness to take risks with a 30+ year old launch system) there will be a gap in the United States' ability to launch astronauts into orbit until Orion is available.
The deadline in the VSE for Orion's first launch is March 2015, but NASA always thought they could get it done a little earlier, possibly as early as 2013, in an attempt to shorten the gap in launch capabilities. Unfortunately, their hopes have now slipped to September of 2014 as the earliest possible launch date for Orion due to insufficient funding from Congress.
My opinion, though, is that NASA won't hit that September 2014 date, or even the Congressionally-mandated March 2015 date due to the amount of work still to be done and the uncertainties that crop up along the way. A while back it was revealed that the Orion launcher has problems with vibrations that could possibly shake the astronauts to death. The solution they came up with involved—get this—using springs to dampen the vibration. That's right, it took them six months to come up with the idea of using the same technology that your car uses to reduce the amount by which you feel bumps in the road.
The bureaucratic nightmare that is the U.S. government takes six months to put springs under the astronauts' seats... figuring out the complicated parts of a launch system (and testing it until it works reliably) will likely take considerably longer.