I have found most confidence contributing to the Red Cross (in my
country of residence) as well as a monk from Sri Lanka. Perhaps these
links will be helpful to others who wish to make donations. The Sri
Lanka Government seems to recommend sending donations via the following:

http://www.emergencydonations.gov.lk/

For residents of the United States:

The Bhavana Society (as well as the US Embassy of Sri Lanka)
recommends sending donations to the SRI LANKA DISASTER RELIEF FUND.

http://bhavanasociety.org/bhavana.asp?f=assistSriLanka
http://www.slembassyusa.org/

SRI LANKA DISASTER RELIEF FUND

Contributions to the ongoing Sri Lanka relief efforts can be made by
cash, check or wire transfer.

** Please note that the Sri Lanka Disaster Relief Fund is not tax
deductible**.
Checks and wire transfers should be made out to "Sri Lanka Disaster
Relief Fund"
Please note that deposits can be made at any Wachovia Bank or branch.

Wachovia Bank,
1300 I Street, NW,
Washington DC 20005

Swift: PNBPUS33

ABA#: 054001220

Account: 2000024529976

Questions related to Wachovia Bank account please call: 1-800-922-4684

Credit Card Contributions can be made by calling your credit card
company and providing them with the account information listed above.
At this time Wachovia Bank is unable to process online credit card
payments. We regret any inconvenience caused.