The big web sites are making a big mistake in not responding to Katrina the way they did to the Tsunami relief effort. Google is sitting on its thumbs rationalizing why they can't put up a Hurricane Katrina donation link. Amazon was doing the same, until some bloggers pushed them along.
Hopefully Google will get on board. If they don't it'll be a huge mistake. In the meantime, make a donation of your own to the American Red Cross or another deserving charity.
Update: Google finally put up a donation link - it goes to Amazon's Red Cross page. I imagine the Google people were wringing their hands over not fire-hosing a given charity. But three days to figure this out... At least they are on board, even if belatedly.