The poorest nation in the Western Hemisphere, Haiti, was hit with a 7.0 earthquake Tuesday afternoon.  "Most of Port-au-Prince," the capital, "is destroyed":

Associated Press reporters toured city streets in Port-au-Prince late Tuesday and early Wednesday and described scenes of severe and widespread damage and casualties. It was clear that many people had died and thousands were left homeless, they said.

They saw women covered in dust clawing out of debris and wailing. Stunned people wandered the streets holding hands, they said, while many gravely injured people sat in the streets early Wednesday, pleading for doctors. Thousands of people gathered in public squares late into the night, singing hymns and weeping.

When the 2004 Indian Ocean tsunami hit, my $50 went to Catholic Relief Services, which has an outstanding infrastructure in the affected area.  They appear just as capable and effective in the Caribbean, so if you're looking for an organization to put a donation to good use, here's a recommendation from me. The Red Cross is also soliciting donations, and according to this you can text HAITI to 90999 to donate $10 to the organization's relief efforts. 

Haitian musician Wyclef Jean was urging people to text Yele to 501501, charging a $5 donation to your cell phone bill and helping the Yele Haiti Earthquake Fund.  Jean told CNN that "the majority of [Haiti's] 8 million residents live on less than $1 per day. Unemployment is close to 80 percent, and more than half the population is under 21 years old. Haiti is the poorest nation in the Western Hemisphere."