In these days Mullahs say that the uprisings in the Middle East are a sign for the Apocalypse. They think that Mahdi is behind the Egyptian revolution and the uprisings in other countries. Mahdi is the Islamic Messiah. In fact, In Islamic eschatology, the Second Coming of Christ is preceded by the appearance of the Mahdi. Twelver Shiah Muslims believe Mahdi is the 12th Imam, who was hidden by God following the death of his father in 9th century AD and will reappear as “ The Restorer of Religion and Justice who will Rule before the End of the World” Khamenei and AN (AhmadiNejad) both are Twelver that means ‘belief in and efforts to prepare for the Mahdi’. Indeed, AN is a religiosity, like George W. Bush. Bush was convinced that “God wanted him to be president”. He and the American Taliban see themselves as fulfilling biblical prophecy in the Middle East. The evangelical Christian Zionist movement see in I-s-r-a-e-l “a fulfillment of the biblical prophecy about the second coming of Christ”. Some friends of Bush are not content to wait for the Second Coming of Christ. They think that the arrival of the End of Times should be prodded, advanced and cajoled. That is what many scholars described as ” Apocalypse Politics ” In Iran we have an Islamic version of the Apocalypse Politics, too.
Khamenei believe he is in touch with the Mahdi . A key Mullah in Qom said that our candidate list for the Parliament was singed by the Mahdi. .Khamenei and AN say that the subsidies and that 40$ that they pay to each person is the Mahdi’s money When AN and his friends want to eat something, they put an extra plate for the Mahdi. AN has a very close association with Ayatollah Mesbah-Yazdi and the shadowy Hojjatieh Society . Hojjatieh Society has developed fanatic concepts, including one which justified the instigation of societal chaos, so as to augur the return of the Mahdi. Using this belief as their guide, Hojjatieh members refused to become involved in the 1979 Revolution, believing the Shah’s missteps to be the perfect spark for the return of the Mahdi. Considered so extreme that Khomeini formally banned the group in the early 1980s, the society was forced to move underground. However, it is widely believed that the philosophy of Hojjatieh survives, espoused by numerous theological schools in Iran, the most prestigious being the
Hojjatieh-founded Haqqani school in Qom. Haqqani’s most famous graduate? Ayatollah Mesbah-Yazdi Mesbah-Yazdi has also suggested that killing “intellectuals” is sanctioned by God himself, and that “pluralism” is Satanic trickery. Additionally, the internal security agencies have been placed under the command of Mesbah-Yazdi followers . Indeed, Khameni, AN, and all Hojjatieh followers want to prepare the grounds (enough corruption) for return of the Mahdi.
But How will Mahdi come? Through an Apocalypse and an Armageddon . The Mahdi or Imam Zaman (“the ruler of time”) will emerge from his “Occultation” in order to liberate the world from evil. When the world is full of corruption, he will come and lead the fight against Dajjal (Islamic Antichrist) and the corrupt world (Mullah say that it’s Western society) and defeat them in some kind of Armageddon’s battles. After that the world will be full of justice and the earth will be prepared for the Last Judgment and the Resurrection. Jesus is said to return to the earth to help the Mahdi. He will be a faithful Muslim. He will destroy Christianity and will establish Islamic Shariah (Law) throughout the entire earth. It is like the belief of fanatic Christians and Jews. To fanatic Jews, the long-awaited Messiah will return to become the king of I-s-r-a-e-l and high priest of a rebuilt Temple For fanatic Christians, he return at the height of the battle of Armageddon , that it will require a Third Temple from which the Lord will begin a millennial reign. In fact, according to some premillennial Christian interpretations, the Messiah will return to earth and defeat the Antichrist in the battle of Armageddon. Then Satan will be put into the “bottomless pit” or abyss for 1000 years, known as the Millennial Age. After being released from the abyss, Satan will gather Gog and Magog (It’s a Persian myth! ) from the four corners of the earth. They will encamp surrounding the “holy ones” and the “beloved city” (Jerusalem). Fire will come down from God, out of heaven and devour Gog and Magog after the Millennium, and the Devil who deceived them is thrown into Gehenna (It’s a Persian word! and means “Hell”). Indeed, Millennialism is a doctrine of Zoroastrianism, the ancient Persian religion [*]
AN is like Bush. He pray a lot, even before the UN General Assembly. He has an special pray that says: “ O Mighty Lord, I pray to you to hasten the emergence of your last repository, the promised one, that perfect human being, the one that will fill this world with justice and peace … God, I pray to you to hasten the the emergence of Mahdi (Second Coming of Mahdi), our Master. Please keep us among his supporters and warriors. ” On returning to Iran from New York, AN recalled the effect of his UN speech: “One of our group told me that when I started to say “In the name of God”, he saw a light around me, and I was placed inside this aura. I felt it myself. I felt the atmosphere suddenly change, and for those 27 or 28 minutes, the leaders of the world did not blink. they were rapt.” AN said that he has evidence that the US was trying to prevent the coming of the Mahdi, he said: “We have documented proof that they believe that the Mahdi will raise in these parts [Middle East] and he will dry the roots of all injustice in the world. They have devised all these plans to prevent the coming of the Hidden Imam because they know that the Iranian nation is the one that will prepare the grounds for his coming and will be the supporters of his rule”. AN reiterated his role in the return of the Mahdi: “Our revolution’s main mission is to pave the way for the reappearance of the 12th Imam.” Twelvers consider it their responsibility to cause the apocalyptic conditions that they believe will surround his return
There are eerie parallels between Muslim and Christian fanatics in Iran and the US. They have analogous views regarding religious prophecy, second comings and the End of Times for their respective Christian and Shiite faiths. While Mullahs in Tehran look to the return of the Twelfth Imam to deliver them from evil, Christian fanatics in the US await the Second Coming of Christ to usher in a millennium of peace. With their research institutes and breeding programs, the devout on both sides seek to accelerate the End of Times
[*] The Zoroastrian doctrine of heaven, hell, and limbo influenced other faiths. Islam absorbed not only the ideas of heaven, hell, and limbo, but also the scheme of individual judgment at a celestial bridge and the notion of final, universal judgment. Christianity further assimilated the Zoroastrian belief of the soul’s afterlife and the appearance of a savior, resurrection, and eternal life at the end of the world. Zoroaster’s notions affected the development of Judeo-Christian beliefs about demons and angels, the afterlife, and heaven and hell, as well as the concept of resurrection of the dead at the end of time . 
some good references for further reading:
 The 12th Imam
 Encyclopedia Britannica and Encarta Encyclopedia.