1. Check out the IRS website (IRS.gov), and go to "Exempt Organizations Select Check," which is designed to help donors find "legitimate, qualified charities."
2.You can also look for qualified charities on the website of the Federal Emergency Management Agency (fema.gov).
"Be wary of charities with names that are similar to familiar or nationally known organizations"... "Some phony charities use names or websites that sound or look like those of respected, legitimate organizations." . . . "For security and tax-record purposes, contribute by check or credit card or another way that provides documentation of the gift." For more details, see IRS Publication 526.
(sources for this post: IRS and Wall Street Journal)