Via Alison, here's a grassroots group called The Sparkplug Foundation which has a list of less well-known, local groups that are making a difference in the Gulf Coast region. It lists groups like the Federation of Southern Land Cooperatives, St. Mary Community Action Association, Plenty International, The Justice Center, National Youth Advocacy Coalition / NCLR, Louisiana Domestic Violence Victims' Hurricane Relief Fund, AIDS Alliance, and many others.
Go to the link and shop the list. I'm also adding the Sparkplug link to my sidebar, under "Activist & Humanitarian".
UPDATE: FWIW, I just donated 100.00 to the FSLC. Do what you can.