In Japan:

セカンドハーベスト・ジャパンは、生活に困っている人々と彼らの支援団体を食を通じてサポートしている特定非営利活動法人（NPO）です。
English: http://www.2hj.org/index.php/news/send_us_food_and_supplies/日本語：http://www.2hj.org/index.php/news_j/disasterrelieffooddonations/

Outside Japan:

Donate to Japan Disaster Relief here: 

For more information: http://www.google.com/intl/en/crisisresponse/japanquake2011.html

Below is a comment left on an article about American airline flight attendants being concerned about flying into Tokyo.

My wife was Purser on a flight descending into Narita, Tokyo’s International Airport, when the earthquake struck. Her flight eventually ended in Osaka. When the crews were returned to Narita they visited shelters and left what food they could find as well as their own jackets, scarves and gloves.

Upon returning home, two days later than scheduled, she put out a call for warm jackets and cold weather gear. She and other crew members also purchased, out of their own pockets, as much preserved milk and flashlights as they could carry.

Yesterday the crew returned to Narita with more than 20 large bags of jackets, blankets, gloves and the milk and flashlights. Our entry way is still stacked to the ceiling with more jackets and clothing that will be going in every day with the flight attendants.

Were they nervous about it? Of course. How could one not be worried with the legions of science illiterate reporters spreading hysteria? Still they went to work and are doing far more than their jobs require.