Hey, did you know that today is the 32nd anniversary of the victory of the Khomeini forces in Iran? It is celebrated there as the national holiday “Islamic Revolution Victory Day,” Iran’s un-Fourth-of-July.
If you follow the timeline of the revolution in Iran, you will see the following sequence of cascading events: huge demonstrations in late December of 1978, the Shah appoints Bakhtiar PM on January 3 of 1979, the Shah flees the country on January 16, Khomeini returns February 1 and re-appoints Bakhtiar on February 4, Khomeini tells his followers on February 10 to ignore a Bakhtiar-imposed curfew and pandemonium follows, and on February 11 the regime collapses and Bakhtiar flees.
One very large difference between Egypt and Iran is that Iran had a ready-made charismatic figure in Khomeini, who was ruthless in his drive to power. Egypt seems to lack a similar figure—so far.
[Hat tip: commenter "sergey."]
[ADDENDUM: Here's another anniversary from the history of Iran, one that's not celebrated by anybody: on November 5, 1978, the Shah went on TV and promised "not to repeat past mistakes and to make amends saying, 'I heard the voice of your revolution... As Shah of Iran as well as an Iranian citizen, I cannot but approve your revolution.'" Something like yesterday's address by Mubarak, wasn't it? And just about as effective.]