Protect Yourself
During emergencies (earthquake/tsunami/flooding), information is automatically sent to mobile phones registered for the service. Please visit this site to sign up your keitai:
http://bosai.net/e/

Information about how to create an emergency kit and evacuation card can be found here: http://ajet.net/tag/emergency-procedures/

Volunteering
As the infrastructure improves and becomes able to support more people in the area (right now, the concentration is on making sure there is enough water, food, and heat for the victims of the disasters), many volunteers will be needed to assist in cleanup efforts. As of right now, most volunteer duties involve collecting and sorting supplies for the victims. These website with information about volunteer work for quake and tsunami relief will be updated as time goes on:
http://ajet.net/lang/en/2011/03/16/volunteer-information-for-people-in-japan/
http://japanvolunteers.wordpress.com/volunteers/

Giving
Money
Man Up for Japan  (http://www.facebook.com/event.php?eid=198359066854878) is AJET’s way of encouraging people to donate to the charities of their choice.  While the easiest way to give is donating locally into boxes and collection bins, if you really want to make sure your money is going directly to disaster relief, it pays to do a little research. There are many big organizations involved in the disaster relief efforts, and they all have many projects going at one time. You will want to indicate where and when possible that your donation is meant for the Tohoku disaster relief. See these donor tips for more information: http://japanvolunteers.wordpress.com/donor-tips/

Having said that, the Japan Red Cross (http://www.jrc.or.jp/english/index.html) is definitely a good sturdy option. You can donate to the Japan Red Cross in a number of ways, including at the FamiPort terminals in Family Mart, Post Office counters, and online (the google crisis response page has a feature for this). Most of what you donate into collection boxes/cans/modified PET bottles will likely go here as well; disaster relief is something that is going to take a long time and lots more resources, so keep on putting your okane in those boxes!
Other groups and associations are also accepting donations. For more information about donating rice, e-mail Barry Wyatt at barry@kozmoz.org. The following is a list of direct donation information for several organizations. Give the list a look and if you haven’t already, donate to your favorite. For example, when I 万ed up, since I have a PostBank account (and transfers are fee-less), I chose number 4 and number 7 on this list:
http://japanvolunteers.wordpress.com/japan-donations/

Talent

Creative projects for Tohoku include Write for Tohoku, and the music project TerraNoble:
http://terranoble.org/
http://writefortohoku.wordpress.com/

Stuff

The City Office in Himeji is accepting materials for disaster relief. I believe they really want blankets, towels, and underwear (all new/unused items). They aren’t taking used items at this time.
http://www.city.himeji.lg.jp/koho/press/_23638/_24108/_24391.html

Blood
The Japan Red Cross is always accepting blood donations. The second website shows how much they currently have or need.
http://www.jrc.or.jp/donation/index.html
http://www.hyogo.bc.jrc.or.jp/

Google Crisis Response
Google’s succinct (and international) homepage for all things Tohoku disaster: http://www.google.com/crisisresponse/japanquake2011.html