So the US intelligence services disseminated a new National Intelligence Estimate in which they've changed their appraisal of the Iranian nuclear weapons program. Now they think that Iran probably halted a covert nuclear weapons program they'd run since the 1980s in 2003 and probably haven't restarted it since. At the same time, they think that Iran probably couldn't build a nuke before 2009 even if it wanted to, but almost certainly could create one after 2015, again, if Tehran wanted to.

Here's the public-consumption version of the NIE:

http://www.dni.gov/press_releases/20071203_release.pdf

The actual estimate starts on page 6, before that it's one huge disclaimer about how they can never be completely certain of anything. <_<