Interior Ministry employees (who were supposed to monitor and count) said that votes were never tabulated - they just received them, and a number was arbitrarily assigned to each candidate. (Somewhat conflicting, I've been told that the votes were actually counted by low-level officials who told Mousavi that he was winning, only to have higher-ups announce a "revised" total that showed Ahmadinejad with 60%.)
Newspaper offices have been occupied, and phone and internet has been out in Tehran for over a day. People are twittering the news, if you can believe that.
Apparently the Rvolutionary Guards conducted their own poll a week before the election. It showed Mousavi ahead by double-digits, where had been essentially tied with Ahmadinejad a few weeks before. They panicked.
