Did you get e-mail asking you to contribute to Katrina relief? Unfortunately, many such requests are fraudulent.
After every natural disaster in recent years, spammers have always sent fake appeals, preying on the good intentions of generous Americans. It happened after the tsunami, and it was sadly predictable that it would happen now.
FEMA, the Federal Emergency Management Agency has a web page listing reputable organizations accepting donations. We encourage you to check their list before donating to a charity that you're not already familiar with.