Laura Freschi posts an e-mail from Saundra Schimmelpfennig, veteran of the 2004 tsunami relief effort and author of the blog Good Intentions Are Not Enough:

Immediately after a disaster is prime fundraising time for NGOs. So they all rush in and put out immediate appeals before there’s any clear idea of what or how much they can actually help. Only fund those that already have an office established in country because of the amount of time and money it takes to get anything more than just search and rescue up and running. If you want to move into anything such as temporary shelters, food distribution, those with an already established presence will know the people and systems better and be able to work more quickly and less expensively.

Laura Freschi has a few suggestions for where to give. One NGO collecting medical aid is Merlin USA. Food For The Poor is also a reputable group.