One of the best ways to donate any financial aid is through the American Red Cross. You can go directly to their website which is: http://www.redcross.org.
Then -Select "Haiti Relief and Development" from the list (as of this writing it's the second one down) and hit Continue.
Can't donate money? Donate rice -- for free!
The World Food Programme has a sister support site that most of you probably know about. FreeRice is helping to support the victims of the Haitian earthquake by donating rice. Though the website and its donations are not strictly Haitian, I'm positive that much of the rice donated in the coming days will be going toward Haiti and the surrounding areas.
And you can help by just playing the game. For every vocabulary word you answer correctly, 10 grains of rice are donated toward the cause. There are also other subjects, such as languages, basic algebra and multiplication, English grammar, and geography. Just click the 'Change Subject' link to choose a new subject!
The best part is, the game is completely free for you to play, and you can give as much or as little as you like. Every little bit helps, especially in a time like this.
The Hunger Site is another way you can help. By clicking one little button every day, money and resources will go to help Haitian victims. One click -- how easy does it get?
FreePoverty is a website similar to FreeRice, where you can play a geography game to donate cups of water. The closer you are to the target, the more cups you can donate!
So just because you can't give money doesn't mean you can't help! Help now and save millions of lives.