So one of the enormous problems with the Haiti rescue efforts right now is, not surprisingly, US government policy. We're not letting in necessary airdrops of supplies like water, food, clothes, etc.
I don't know what anyone outside of the US can do about this, but those of us who live in the US can put pressure on the government to lift the restrictions so the aid organizations to which we've been sending money can actually get the supplies to the people who need them.
Go to this page http://salsa.democracyinaction.org/o/1439/p/dia/action/public/?action_KEY=2065 and use it to send emails to your representatives, but DON'T STOP THERE. Call the numbers listed for your reps and ask them to "press the Obama Administration to lift military restrictions preventing aid groups from bringing aid into Haiti and to expand airdrops of water, water purification tablets, and food."
THEN, call the White House switchboard at 202-456-1414 and ask them to "lift military restrictions preventing aid groups from bringing aid into Haiti and to expand airdrops of water, water purification tablets, and food."
Doing all these steps (sending three emails through that site and making four calls--one to each senator, one to your congressperson, and one to the White House) should take you maybe 15 minutes.
THEN, email, tweet, FB supdate, text, etc. all your friends and ask them to do the same thing.
It's criminal that the help is there and our government isn't letting it in. If we bang on the door hard enough they have to let us in, so spread the word and get mad.