Just in case you were wondering, John McCain's now well-publicized gaffe on Al Qaeda in Iraq, in which he blamed Iran for arming and training AQI, was the subject of a report from the American Enterprise Institute in February. No surprise: AEI agrees with McCain that Iran backs Al Qaeda. (There's no evidence that Senator Lieberman, who whispered in McCain's ear to correct his misstatement, plans to whisper in AEI's ear as well.)

Here's a link to the AEI report, issued February 19, called "Iranian Influence in the Levant, Iraq, and Afghanistan":

From the beginning, Iran did not confine its support of anti-American fighters to Shia groups. It also supported Ansar al-Islam, a radical Sunni terrorist group with close ties to al Qaeda. ...

More recently, Iranian arms dealers have supplied new weapons to al Qaeda in Iraq. A supply of armsflowed from Iran into al Qaeda strongholds in Salman Pak and Arab Jabour, presumably from the Iranian border to the south and east. From there, al Qaeda transported the munitions to Baghdad. Iranian arms became an important part of al Qaeda’s arsenal. ...

Whatever Tehran’s intent might be, it is clear that Sunni insurgents, including al Qaeda terrorists, have received Iranian aid in the form of sanctuary within Iran and advanced Iranian-supplied weapons. It is reported that some of them also received training in Iran.