Here are some ways to help (mostly taken from the Japan Times list:
The Japanese Red Cross:
English site: http://www.jrc.or.jp/english/relief/l4/Vcms4_00002070.html
Japanese site: https://gienkin.jrc.or.jp/
- American Red Cross
- British Red Cross
- Save the Children
- MercyCorps
- World Vision Canada
- Ekokoro.jp (Japanese)
- The Japan Committee for Unicef (Japanese)
- GlobalGiving
- Oxfam Japan
- Salvation Army
- Second Harvest
- Send money or supplies via JHelp (Scroll down page for mailing address.)
- Blood donation. Call Japan Red Cross Society at 03-3437-7081 and checkguidelines for blood donor eligibility
Japanese students in the UK have organized an appeal effort there for the Japanese Red Cross: http://japanearthquakerelieffund.jimdo.com/
If you are in the US, you can find a list of charities here: http://www.huffingtonpost.com/2011/03/15/how-to-help-japan-earthquake-relief_n_834484.html
-Adam