In the meantime, the Disasters Emergency Committee
is a good place to send cash.
The DEC is an umbrella organisation which raises funds and distributes them to its member organisations:
British Red Cross
Help the Aged
Save the Children
To my mind the big benefit of donating to the DEC appeal, rather than directly to an individual charity, is that the DEC works to coordinate the overall effort. From the DEC FAQ:
The DEC operates a monthly draw down system. Agencies withdraw money from the DEC on a basis of actual expenditure and one month’s forward cash flow projection. Each agency has to submit plans to the DEC within 4 weeks with details of the humanitarian relief work they intend to carry out. Discussions are held on quality, potential overlap, real needs and capacity of DEC agencies. The work detailed in the agency plans must be completed within a year.