Despite any irregularities or outright fraud it's pretty clear that most Iranians did in fact vote to re-elect Ahmadinejad.

from Newsweek:

"What happened to all those charming, articulate young men and women in North Tehran, interviewed again and again on Western television? They were so enthusiastic about Ahmadinejad's main opponent, former prime minister Mir Hossein Mousavi. They were excited about the prospect of more freedoms. They thought Ahmadinejad was a failure and an embarrassment, and they really seemed to like us Americans. Indeed, they seemed almost to be like us Americans. Didn't they speak for the real Iran?

Actually, no. It appears that the working classes and the rural poor—the people who do not much look or act or talk like us—voted overwhelmingly for the scruffy, scrappy president who looks and acts and talks more or less like them. And while Mousavi and his supporters are protesting and even scuffling with police, they are just as likely to be overwhelmed in the streets as they were at the polls."