Iran is fighting a proxy war against the West against by using terrorist groups as its army. Groups like Hezbollah, Ansar Al Islam, and even some franchises of Al Queda are funded and armed by Iran. Although Iran claims to pursue peaceful goals in the middle east, its backing of any terrorist group opposed the United States reveals it true intentions.
Hezbollah is Iran's proxy army to fight Isreal, although Isreal has never conducted operations against Iran. Iran funds and trains Hezbollah through direct contact in Lebanon and from camps in Iran. IGRC (Iranian Republican Guard Corps) officers routinely meet with Hassan Nazrallah, a fact Nazrallah has admitted to in the press while thanking the Iranians after last year's war against Isreal.
IGRC also provides weapons technicians and weapons experts for some of Hezbollah's more complex weaponry, such as the anti-ship missle that struck an Isreali warship off of the Lebanese coast during the war.
Ansar Al-Islam is a Kurdish-Sunni terrorist group formed in 2001 from several smaller kurdish extremist groups. It was heavily involved in fighting in Northern Iraq prior to the US invasion in 2003, and stated as it goal the establishment of an Islamic Kurdistan. AAIs ideology is nearly identical to Al Queda and they attempt to establish a Taliban like rule wherever they set up camp. Iran supported AAI prior to 2003 because of its opposition to Saddam Hussien and its opposition to the Kurd groups that were conducting attacks in Iran.
Iran supports AAI now to weaken the US influence in Iraq. AAI has an extensive European network, run out of Norway by its leader Mullah Krekar. Iran will probably use AAI to conduct attacks in Germany and the UK if the coalition forces in Iraq attack Iran.
Iran backs several of Al Queda's franchise organizations in the Middle East in order to weaken US influence and weaken the governments of UAE, Qatar, and Yemen. Iran will be able to export its Islamic Revolution more successfully if the governments of its target countries are less influential.
Supporting Sunni terrorist groups seems counter-productive to Iran's goals, but Iran has a very utilitarian approach. It throws its support to whatever terrorist group can achieve its national goals at that time, be they sunni (AAI and Al Queda) or Shia (Hezbollah). Iran is not pursuing a peaceful agenda, and is using its minimal diplomatic efforts to stall and delay US and EU efforts to stop its nuclear program and encourage democratic reform.
We are currently at war with Iran, or at least with its proxies, and Iran is the agressor.