The US went along with the plan, after the Dulles boys did a Red-scare number on President Eisenhower, making him think Iranian Prime Minister Mossadegh was going over to the Soviet Union. But before any of that happened, BP was the issue. Called the Anglo-Iranian Oil Company (AIOC), they basically screwed Iran out of most of their oil money. They negotiated a deal with a corrupt leader, and when more responsible Iranian leaders came into power and tried to renegotiate a fairer split of the money, AIOC/BP refused. Britain's initial request for an overthrow of the Iranian regime was denied by President Truman. Eisenhower wasn't really game, either. The US was disgusted at AIOC/BP - it was obvious the deal was unfair, and they wanted them to renegotiate. Eventually, the Dulles brothers resorted to fear of Communism (I think they really believed it, though classified records revealed since then show the threat wasn't that substantiated) to get the US to back Britain, and Mossadegh was overthrown by a team led by CIA operative Kermit Roosevelt Jr. (Teddy's grandson), and Mohammad Reza Pahlavi was put in power. Pahlavi, of course, is better known as "The Shah", the man whose ruthless rule, which the US backed, led to a major backlash in the 1970s that eventually led to the Iranian Revolution in 1979. So yeah, that didn't go so well for America.
At the center of all this was BP/AIOC. Their unwillingness to negotiate a fairer deal with Mossadegh led to all of this. Steve Kinzer has written quite a bit about this episode, most notably in his fantastic book All the Shah's Men. Here is a recent interview he gave on the topic. So, yeah, thanks a lot, BP. You're screwing America yet again. You can bet a lot of people in Iran are chuckling as they hear more about this situation in the Gulf of Mexico. They know all too well the destruction this oil company has wrought.