Corporations, Katrina and Disaster Relief

Wal-mart announced that it would "donate $1 million to the Salvation Army for relief assistance such as meals for victims and emergency and rescue personnel. The retailer said it would also accept customer donations nationwide at all of its stores this week as well as credit-card contributions through walmart.com."

Is this too much or too little? (Remember, they are donating shareholders' money.) How much should corporations give, if any at all? What resources should they make available? Answer in comments.