I'm sure you are all asking yourselves that as you watch the images come out of Haiti.
Of course, first and foremost, we should all pray. Pray for those whose lives have been upended by the earthquake and those who are ministering to them.
Secondly, we can give money. While there are many worthwhile organizations (and I'm sure, many who are not), one that I trust is Compassion.
They are having a special deal right now, see:
Not only are they reputable and already there, but they do all their work in the name of Jesus. I encourage you to do what you can.