I don't have much to say, except that, if you are at all interested in this story, just keep reading Andrew Sullivan. Constantly. The NY Times' blog The Lede has also been comprehensive and extraordinary.
The one thing that seems clear is that the people running Iran, the clerics, do not understand democracy. You can't promise a fair election, get people's hopes up, and then steal it this blatantly. People do not rebel when they are oppressed and beaten down; they rebel when they are hopeful that they are beaten down and oppressed and suddenly some kind of hope arrives. That's when they rebel.
I vaguely remember the Shah going down. What I remember is that it seemed to take a long time - he hung in there as long as he could. That will probably be what happens here. This is not over, not by a long shot. There are a number of Iranians who really did vote for Ahmadinejad and really do believe that he is on their side. He may very well be on their side, but there seem to be a lot more Iranians who believe that he stole this election.
One thing that makes me proud is that a lot of the inventions that are being used to circumvent the government's attempt to control the people - Twitter, Facebook, Flickr - were invented by Americans. If you really get down to it, the same can be said of the Internet itself. And, going way back, even the telephone.
I have to admit that when I first heard about Twitter, I didn't think it was an interesting idea. Too shallow, kind of silly. I don't think that any more.
As Andrew Sullivan keeps posting, "Know hope."