You won't hear it from the Obama administration, but there are several indications that al-Qaeda in Yemen was assisted by Iran in setting up operations there and that one of the bomb plotters visited Tehran just before the bombing.

From an editorial in the Washington Times:

Iran and al Qaeda have made mutual war on America in Yemen before. In November 2008, Western security officials intercepted a letter signed by bin Laden deputy Ayman al-Zawahiri thanking Iran for its "vision" in helping al Qaeda establish a foothold in Yemen after being routed from Iraq and Saudi Arabia. The terror leader praised Tehran for its "monetary and infrastructure assistance" related to a September 2008 attack on the U.S. Embassy in Yemen's capital Sana'a. Sixteen people were killed in the attack, which featured machine gun and rocket fire supporting a double suicide car bombing.

Last January, Saudi Guantanamo alumnus Mohammed Atiq Awayd al-Harbi (a.k.a. al-Awfi, or detainee No. 333) turned up in a videotape as a leader of the newly formed al Qaeda in the Arabian Peninsula, the organization that recruited Flight 253 bomber Umar Farouk Abdulmutallab. Al-Awfi had been released to Saudi custody in 2007 and went through Saudi jihadist deprogramming before being set free. He turned himself back in to Saudi authorities in February 2009 and testified that Iran was involved in supporting Shi'ite rebels in Yemen, and was also making cash available to al Qaeda.

Some intelligence analysts downplay the idea of cooperation between al Qaeda and Iran because the two are ideological foes. But both detest the United States and have mutual interest in collaborative efforts that hurt U.S. interests.

You may also recall that Iran has provided "safe haven" (house arrest") to many al-Qaeda operatives after 9/11 and that some of bin Laden's relatives have taken refuge there.

Iran has shown that it will work with anyone opposed to America - Hamas, the Sunni insurgents and al-Qeada in Iraq - and that theology takes a back seat to common interests in trying to kill Americans.

Hat Tip: Ed Lasky