Needless to say, Iranians will spare no effort pointing out that they are not arabs, and their past bloody episodes involving the Iraqis and the Osama sponsored Taleban tend go against their actively partaking in any guerilla activities directed against us in Iraq. They appear to me instead to be waging a campaign of Mullacide, attempting to gain control of the clergy through which they can apply political leverage.
This isn't to say they're not enjoying our troubles there, but I have yet to see strong evidence of either Al Qaeda or Iranian influence amongst the Baathist Fedayeen, (as opposed to Ansar al-Islam, which has ties to pretty much everybody we'd like to see dead and buried, but, as a Wahabbist organization dependent upon Shiite Iran for its supplies, exists to provide leverage against the Kurds more than anything else and is a dead end as far as exerting real control in Iraq.)
I would note that our security in the Balkans is no worse nor better than it is anywhere else by virtue of our actions - it is better because the locals aren't either out to kill us or supporting those who are, as was the case in Aidid's corner of Somalia, or is still the case in large parts of Afghanistan and Iraq.