Cut all the b.s., humans are naturally out for their best interest (sometimes with the exception of family and close friends). Nations are no different. I don't think anyone is right or wrong in this situation and I can see both sides of the arguement.
Given the United State's brazen attitude to attack Iraq without the consent of the U.N., I cannot blame Iran for wanting to arm themselves with nukes as a means of defense and future bargaining power with countries such as the U.S. and Britian.
On the opposite side of the coin, I would fully expect the U.S. to oppose nukes in Iran and expect them to stage a premptive military strike if they feel the nukes could be used in an attack against America in the future.
I think it's a matter of what side of the coin you fall on. As an American, I fully admit I have my best interest (and those I care about) at heart. As a result, America should take out the current regime in Iran and erradicate their nuclear program.