I'm beginning to think that the key factors are
-geography: a shared culture, language, ties to nearby countries that provide a sense that "it can happen here!"
-the number and size of existing non-governmental organizations -- the strength of the *organized* opposition movement
-nonviolence: a mass movement that uses nonviolent action to mobilize the most people and avoid a civil war
-media coverage: ideally live video
Now there isn't too much that foreigners can do to help regarding geography and non-governmental organizations. We could help out with trainings but it might be a bit late for that.
What we need is to have 100-1000 citizen journalists who are already living in the 10-20 countries that are most likely to have successful revolutions. We need to train people to upload video. Ideally we want live video on Al-Jazeera of the protests to encourage nonviolence and thus the largest protests possible (people are less likely to protest if it is an armed battle between two sides). We need people who are already on spot who will be able to avoid getting picked up by the state security.
My guess is people already have video cameras and (depending on the country) laptops. They need modems. And they need to know how to dial up to get internet access from outside of their country. That will work for non-live video clips. For live video, it will be possible so long as a country keeps its high speed internet up.
I'm not sure if it is possible to run good quality live video over a satellite phone (aka videophone). These are pricy ($500-$1000, and $1/minute), but could be helpful. The data rate might max out at 33 kbps, which is less than a good dialup modem connection (56k) and a lot less than high speed internet (3000kbps or more). You might be able to broadcast the really fuzzy green images that we saw of Tahrir square (audio with very low speed and low resolution video).
Donate to Avaaz
Avaaz is working urgently to "blackout-proof" the protests -- with secure satellite modems and phones, tiny video cameras, and portable radio transmitters, plus expert support teams on the ground -- to enable activists to broadcast live video feeds even during internet and phone blackouts. I just sent them $1000.