I read an article a couple days ago in a Japanese paper that approx 6,250,000 USD was donated to Japan. Probably through the Red Cross (but I am not sure). The paper says most of them are donated by US citizens.
OK, if you were really serious about this question, I give you this list of donations and other assistance by foreign governments (not including donations from private citizens) from all over the world according to the Sankei Shinbun (a Japanese paper) on Mar 27th, 2011.
US military: 180,000 personnel.
US Navy vessels: 19
US Air Force aircraft: 140
Goods: 230 tons
Food: more than 60,000 meals
USAID rescue team members: 144
USAID rescue team dogs: 12
Financial assistance: 145,000 USD
Nuclear plant specialists dispatched to Japan: 39
Unmanned aerial vehicle: Global Hawk
USF Reconnaissance aircraft: U2
Unti-radiation suits: 10,000
In addition, 450 specialists in nuclear accidents are ready to be dispatched.
A 15-member rescue mission
emergency goods: 30 million CNY (4,6 million USD)
Gasoline: 10,000 tons.
Cruid oil: 10,000 tons.
Republic of Korea:
107 members of rescue mission
53 tons of boric acid (to prevent nuclear fusion inside the nuclear reactors.
161 members of Russian rescue team
170,000 blankets and a large amount of drinking water
28 members of Taiwan rescue team
Financial aid: 3,5 million USD
12 members of Mongolian rescue mission.
Financia aid: 1 million USD
15 members of Indonesian rescue mission
Financial assistance: 2 million USD
drinking water: 20,000 bottles
Financial assistance: 40,000 USD
Financial assistance: 6,7 million USD
donation: 202,500 USD
donation: 101,250 USD
donation: 101,250 USD
10,000 bottles of drinking water
biscuits: 13.5 tons
powder milk: 9 tons
1.5 tons of drinking water
donation: 1 million dollars
75 members of rescue mission
Financial assistance: 10 million USD.
52 members of resmissionsion
32 members of rescue mission
45 members of rescue mission
Financial assistance: 500,000 USD.
a total of 70 tons of goods, including 25,000 blankets; 2,000 mattresses; and 300 sleeping bags.
69 members of rescue mission
134 members of rescue mission.
100 tons of boric acid
anti-nuclear suits: 10,000.
41 members of rescue mission.
27 members of rescue mission
2.5 tons of drinking water
as of Mar 29, 2011
(the Wall Street Journal)
AKB48: 500 million yen ($6.2 million)
Namie Amuro, Japanese pop singer: 50 million yen
Bae Yong-jon, Korean actor: 1 billion won ($889,000)
Sandra Bullock: $1 million
Chen Guangbiao, Jiangsu Huangpu Renewable Resources CEO: 13 million yen
Choi Ji Woo, South Korean actress: 200 million won
Yu Darvish, baseball player with the Nippon Fighters: 50 million yen
Clint Eastwood, American actor and director: $1 million
Ayumi Hamasaki, Japanese pop singer: 35 million yen
Ichiro Suzuki: 100 million yen
Kim Hyung-joong, South Korean actor: 100 million won
Hiroshi Kume, Japanese TV anchor: 200 million yen
Li Ka Shing, Hong Kong investor: $1 million
Elaine Low, affiliated with Singaporean company PT Bayan Resources: $783,000 (S$1 million)
Hideki Matsui: 50 million yen
Park Chon-ho, South Korean baseball player on Orix: 10 million yen
Ryu Si-won, Korean actor and singer: $180,000
Song Seung-hun, Korean actor: $180,000
Tadashi Yanai, Fast Retailing CEO: 1 billion yen
Canon: 300 million yen
Casio Computer: 10 million yen
Fast Retailing: 400 million yen
Fujifilm Corp: 300 million yen
Credit Suisse: $1 million
Goldman Sachs: 500 million yen
Honda Motor: 300 million yen
Kirin Holdings: 300 million yen
Eli Lilly: 100 million yen
Kobayashi Pharmaceutical Co., Ltd.: 100 million yen
Japan Sumo Association: 50 million yen
Jefferies: $5.25 million
Konica Minolta: 50 million yen
Michelin: $1 million
Mitsubishi Electric: 500 million yen
Morgan Stanley: 500 million yen
Nikon: 100 million yen
Nissan Motor: 430 million yen
Panasonic Corp: 300 million yen
Ricoh Co. Ltd.: 300 million yen
Seiko Epson: 100 million yen
Sony: 300 million yen
Suntory: 300 million yen
Tokyo Apache and Evolution Capital, Japanese professional basketball team.: $1 million
Toyota Motor Corp.: 300 million yen
UBS: 100 million yen
Wal-Mart: $5 million