Flickr have created a new group for folks to donate prints of their photos to be auctioned off. Proceeds will be sent to the American Red Cross to aid the rescue effort in the US Gulf States.
The main auction page is here. This is where you'll find the rules; how to donate a print, how to bid, etc.
I'm donating four of my photos - but now the auction has finished, so I've removed the links as they pointed to nowhere! The main-page (see para. above) is still working though, if you want to buy a print from someone.