The recent devastation in Japan has been extremely distressing. I am wondering as a developer what kinds of free software we could come up with that would help in situations like this. Google's people finder for e.g. is a very useful one.
I don't think, apart from very marginal issue (marginal as in we can do without that, and won't feel much difference) free software of any kind would make a difference there.
The list of basic necessities that people need after a situation like that are pretty simple; food, water, clothing, shelter. Those haven't changed for a long time now, and are not likely to change in the near by future.
Software for predicting that we don't need; those needs are pretty obvious.
The problem however, is getting that to the place where it is needed. Let's say two million people are left without housing, and therefore without all the previously mentioned. Two million people = roughly 2000 tons of food, and 4000 tons of water daily. Since transports and distribution is obviously not gonna go there on a daily basis, those packages are usually packed as a weekly supply, meaning, we need roughly 14000 tons of food, and 28000 tons of drinkable water weekly.
(for those counting, that's an average of 1kg of food, and 2L of water daily - I've increased the mass of food, since in there I also putted some clothing; so to simplify the account. Water 2L is a good estimate).
Now, that's 42000 tons of stuff people are gonna need to survive without heating and adequate shelter. I admit, Japan is quite above average in terms of organization and finding shelter for its inhabitants, but still - these are rough statistics.
42000 tons is something out of the question for any kind of air transport. So you can either load up a ship from China or Korea, and send it to the destroyed areas, or you can transport those goods from other Japanese cities.
In either case, to put long story short, and this is where the Japanese work culture and personal discipline are invaluable, it is more a question of transport and distribution than anything else. That and time.