Give what you can!
If you have iTunes on your Mac or PC, this is easiest. No forms to fill out. (100% goes to American Red Cross.)
Text REDCROSS (in all capital letters) to 90999 to give $10 (American Red Cross).
Salvation Army USA's Japan Donations Page.
American Red Cross at redcross.org.
Cruz Roja Americana. Forma en Español.
Canadian Red Cross at redcross.ca.
Canada: Text the word ASIA, in all capital letters, to 30333 to give $10.
ABC News list of relief organizations.