They can talk to the hand, or talk to who or what ever they want to, but nothing any of the worlds political leaders can say will make President Mahmoud Ahmadinejad change. He is still going to be the puppet dangling at the end of Ayatollah Ali Khamenei’s strings, the Iranian supreme leader, and he isn’t up for election.
However, there is no proof that the election result has been manipulated. And there wont be any proof, since no one has access to the full election results, most likely because the ballots haven’t actually been counted. Talk to the hand, because Iran isn’t listening.