The much-hyped IAEA report is out (PDF); . my first impression is that while its overall conclusion (already much leaked in advance) that Iran has been working on a nuclear weapons program is more clrearly outlijed ane documented than ever before, I'm not sure there is a smoking gun to provide those urging an immediate military action with an unassailable excuse to act. That won't stop Israel if it is determined to act, but it also doesn.'t seem to provide a carte blanche.
Unless you're a nuclear physicist or weapons planner, the report isn't light reading; the key part is the "Annex: Possible Military Dimensions to Iran's Nucl4ear Programme,"; which provides the reasoning behind the conclusion that Iran is likely working on a deliverable weapon.
A key source of data for this conclusion is what the report refers to as the "alleged studies documentation," a large collection of intelligence provided tot he IAEA in 2005 by an unidentified Member State. This material, which Iran has claimed is partially forged or fabricated, along with information from 10 Member States and from the IAEA's own investigations, seems to be the primary evidence relied upon. But this information has been in the IAEA's hands for six years; it'z not a last-minute discovery.
As I've already noted, if Israel, or for that matter the US, is determined to resort to military action, defiitive proof may not be necessary: though Colin Powell famously tried to spell out the evidence of Iraqi WMD on the eve of the Iraq war, the WMD never turned up.
I doubt if there are that many non-Iranians who are really convinced that the Iranian nuclear program as wholly peaceful, as Iran claims. But whether this report will tilt public opinion in the direction of military intervention, I'm not sure.
And while we're on the subject, Aaron David Miller at Foreign Policy on five reasons why Israel and the United States might want to think twice before taking any military action.