I plan to make a larger donation than what my small batch of used stamps would raise. It would be such a small, small drop in such a huge bucket.
My church (actually the denomination) that I belong to immediately sent $10,000 from our World Relief fund via Church World Service. Following that gift, every dollar that our local members send with the word Katrina on the check, goes directly for food, water, blankets, tents.... Denomination does not use anything for administration costs.
Sadly, I have heard that there are already people trying to make money dishonestly, using this disaster as a ploy. It is good that you want to send to Red Cross. They are honest. Also the Salvation Army is honest.