I quickly slapped together a little dog-ear graphic for the top-right corner of my page. Clicking the image will take you to The Salvation Army USA National web-site donation page. The page is loading very slowly —I'm assuming due to traffic volume. You can also make a donation at the Canada and Bermuda Territory web-site, but you need to select Other from the Donation Options and specify hurricane Katrina relief in the box.
Update: Here's another SA dog-ear at Andrew Ferguson dot net (he's done a better job of the graphic).