I've overdone this metaphor, but I really do see the panoply of sources we have about Iran as an intelligence service to the masses.
We've got reliable Humint -- on the ground sources. We've got open-source reports from broadcast and newspaper media. We've got analysis, in the form of great aggregation by smart observers. We lack, um, signals intelligence, but Twitter is really a form of SIGINT, isn't it? There's plenty of misinformation out there, like rumors that Ahmadinejad is going to stage an assassination attempt, so we need to be careful about how we judge the information. If we're a savvy analyst, we need to be careful about the weight we attach to photographs and video accounts. They're the most immediate and emotionally powerful, but they can distort our understanding of the situation, particularly of about the importance of specific developments.
To start with, here's the raw data stream from Twitter, with the hashtag of the Iranian election. Remember, this data is unfiltered. There are some nuggets surrounded by garbage. Follow the debates: "(I hear that NPR is claiming that it is false news that Mousavi is in crowd now. IT'S NOT! Tell them pp, we have pics!)" -- that's a real tweet. How would you evaluate it if you were on the Iran desk?
Watch for disinformation. There's a temptation to equate the size of one's twitter follower universe with authority, but that's not logical. This source seems to have good information about Tehran's universities. I'd judge it as reliable because none of the other twitterers are arguing with its conclusions, and there is some independent corroboration for some of what it has to say.
Look for patterns in geography. But don't assume that everything that has the qualities of a pattern is actually a pattern.
Don't assume. Everyone assumes that Mousavi really won. But there is reason to think that the election was very close -- and that Ahmadinejad might have actually prevailed (although the evidence appears solid that his totals were significantly inflated.) Don't assume that Ayatollahs who appear at protests necessarily support the protesters. Don't assume that the Khamenei speaks for the rest of the council of guardians. Don't assume that Iran's government had a plan to contain the protests -- or has a plan for tomorrow, ten days from now, or next month.
Look for sources that disprove your thesis. Go outside the country and outside your comfort zone. See what, say, China's news agency reports about the protests. ("Iran's defeated presidential candidates Mir-Hossein Mousavi and Mehdi Karroubi on Monday appeared in a car at a mass rally in Tehran that has been declared "illegal" by authorities, local Press TV reported.'")