It’s up to the military in Egypt . If they decide Mubarak must go, he will go. And so far today, it looks pretty positive. “Departure Friday” seems to be fairly peaceful, as best as I can tell, and the military seems to be at least somewhat on the side of the protesters. The pro-Mubarak rent-a-thugs seem to be more on the sidelines.
I hope that Mubarak goes into exile, and a leader from the military steps up to establish an interim government to last the bulk of 2011. This would establish enough time for political factions to organize and run in free elections, and would allow the interim government to establish reform laws that would support free elections.
If the elections are held too soon, the Brotherhood is probably the only faction with enough organization, cohesion, and passion to mount an effective campaign and would likely win the country. That could end up with a fundamentalist Muslim government in control of Egypt , and the temptation for them would be to rule tyrannically in the name of God.
I send my prayers.