I am sure you are getting all sorts of news on the post-earthquake situation. Herewith find what I experience here and gather from Japanese media, and a few international students who major in nuclear engineering and earthquake studies who also try to keep fellow student informed but not panicked.
First, about the evacuees. Roads are damaged pretty bad, so there is a big problem in getting food and other supplies to the people in evacuation centers. Most places are still risky for ordinary people to remove debris. Japanese self defense forces and some foreign troops are at work. People use Twitter to tell others which places need which things, and in some places that worked. But in other places, contacting people is a problem.
Now to the nuclear reactors. Initially there seemed to be problems in two nuclear plants in the earthquake-hit area, but now it has been found that one is safe. The other one shut down properly with the earthquake, but the cooling mechanisms failed due to the Tsunami. What you hear in the news are the results of overheating happening in 4 of the 6 reactors in the plant, and what people are doing to control them.
At this moment, the situation is borderline. About 50 professionals remain on site despite all the radiation and heat, trying to put sea water in to these reactors to cool them down. Some amount of radiation will keep leaking until they are cooled down to a lower temperature. There is a chance that they get hotter, in which case there will be more damage to the reactors and stronger leaking of radiation. They are trying to repair the powered cooling systems today, I hope they will succeed. The situation can go either way depending on the result.
The international media coverage has been appalling. CNN asked around from foreigners in Tokyo and posted an article about the ground situation. Headings like "Radiation Soars in Japan" started appearing even before the numbers exceeded the radiation in a dental X-ray. Many foreigners got in panic mode and are leaving Japan, or at least moving down south. At our university, we have a discussion group that analyzes news reports and tell the foreign students what to believe.
Diplomats are in usual business, stroking heads while cutting throats. some embassies issue requests for expats to go back to home countries, where the requests include statements like "Japan's incompetence in handling the crisis....." :-p
How you can help: I will later post a few options for donations. Not for the nuclear stuff, but for supporting the people who are evacuated. I will join a volunteer group once we are allowed to go and help.