I just can't be bothered to dig up all the news stories for someone who is not only willfully ignorant (not paying attention to the news) in the first place, but can't be bothered to google the stories when they are happening everywhere all the time.
EDIT: I'll point you in the right direction, actually. http://www.reddit.com/r/worldnews/search?q=Iran and http://news.google.ca/news?pz=1&ned=ca&hl=en&q=Iran
You're assuming that the medias are objective, not biassed in the slightest. While they are (biassed), and by a lot.
Some demographics. Iran's population is something above 60 millions (ye, I know not everyone can vote, but I won't bother looking at the age and sex structure now). Teheran, along with suburbs, is a dozen or so millions of people. A bit over 1/6th of the population. Mir-Hossein Mousavi did win in Teheran. It's not that hard to campaign in such a densely populated environment, Mousavi used it and that was his main bastion of support. But there's still 5/6th of the country left! And he didn't get all votes in Teheran.
So, yeah. We've got the capital of a huge country rioting, minor riots in few other, big cities, gogo make a revolt! Who gives a shit about other provinces, and the countryside? You, guys, certainly don't.
As for the doubts about counting "only" 10% of the votes again. 10% is more than enough, if they're chosen proportionally from all regions of the country and reflect the age and education structure of the population.
And Mahmud Ahmadineżad isn't some Ajatollah's apprentice that springed out of nowhere. He was the Teheran's mayor before.
Now some history, yay! 22nd of August, 1953. CIA organises a coup against Mohammed Mossadegh, a popular prime minister. Why did they do this? Economy, politics. Mohammed, along with the parliament, were nationalising companies, they didn't want a conflict with USSR (nor did they want communism, on the other hand). The democracy is over, Mohammad Reza Pahlawi is now a dictator, a puppet under American influence. Forced reforms, terror, awareness of the szah's dependency, it all made the people of Iran hate the dictator.
Now think for a while. United States brought down a prime minister who was pretty popular among the population. Democracy is replaced with dictatorship. Wouldn't you be seriously pissed off, on their place? Knowing the foundations, don't you understand the hate towards USA a little more now? Isn't it natural that now, in their own, independent country, they feel better?
Now my personal opinion. I think they might have faked some votes. But even without cheating, Mahmud would still win. I don't know why you can't bear with the fact, that religious fanatics can win elections in other parts of the world.