The BBB runs a website,
http://www.give.org, that tells you what percent of your money's going where. The American Red Cross, where I decided to donate, stacks up pretty well. I don't know if it's the absolute BEST in terms of percentage of money to programs, but a lot of people are donating to them right now. You can also earmark your donations just to go to Hurricane 2005 relief, if you so wish.