According to what I read, Iran already has enough material to build 2 nuclear devices, but to build them, they would have to take certain unmistakable steps, like kicking out the inspectors, which would alert everyone to what they are doing.
Let's not forget that most governements in Europe, America and even the middle east do not want Iran to possess nuclear weapons.
The 2003 invasion of Iraq upset the balance of power by taking out a Sunni regime and replacing it by a Shiite government. This allowed Iran to extend it's influence into Iraq. This worries the other regimes in the region, Syria, Jordan, Egypt and Saudi Arabia which have a Sunni majority.
Saudi Arabia is especially worried because it has a restless Shiite minority in its eastern provinces. Saudi Arabia, since 1948, was one of the most hard line states in its opposition to Israel. Yet, over the past few years, they have held direct but discreet talks with the Israeli governemnt and recently gave the IAF permission to overfly their territory, presumably if it becomes necessary for Israel to attack Iran. The Saudis now realize that Iran is a greater threat than Israel, which is wonderfully ironic.
As usual, the ROW is quite willing to let Israel do the dirty work when it suits their national interest. Just compare the muted response of all governments, including Arab states in the region, when Israel attacked the Syrian reactor in 2007 to the outrage over the botched flotilla raid earlier this year.