There aren’t a lot of natural disasters worse than the earthquake that just struck Haiti. The earthquake is such a disaster that the people who are normally in charge of telling you what a disaster it is are mostly dead or missing.
Earlier, I posted a list of charities that are set up to quickly get relief to those who need it. All of these charities are legitimate and regardless of denominational affiliation are dedicated to providing humanitarian relief. Here’s an updated and expanded list.
Dan’s doing a much better job than I could possibly do on this, so go over there for a better idea of what you can do.