I hope it goes without saying that if you have anything to spare, it would be good of you to donate a bit to the Haitian earthquake relief effort. A few charities that seem worthy to me are:
ADRA, the Adventist emergency relief agency. I haven't been an Adventist in a very long time and would not otherwise counsel giving to a church-affiliated agency, but ADRA does exceptional work during humanitarian crises and is not especially dogmatic in its usual operations.
MSF/Doctors Without Borders. I have always thought they are a fabulous organization that does fabulous work. I read this book a few years ago, and it reinforced that perception.
Lambi Fund of Haiti. I found this through the Charity Navigator web site, and my hope is that donating to such charities will help Haiti recover after the period of urgent crisis has passed and the world's attention has moved on.
Mercy Corps. I don't know much about this charity, but their operational philosophy is very much aligned with my personal beliefs about how positive, sustainable change can be accomplished.
Obviously, I'm not an expert, and I'm sure any reputable and established charity would be fine.