Download a free Web browser toolbar that will alert you if you try to access a known phishing Web site. The Anti-Phishing Working Group recommends Earthlink's ScamBlocker, which can be downloaded for free at http://www.earthlink.net/earthlinktoolbar.
Check your credit card and bank statements and other online accounts regularly to ensure there are no discrepancies.
Make sure your computer has the most up-to-date security patches.
If you receive phishing e-mails, forward the entire message, header included, to the following places:
1) Anti-Phishing Working Group: firstname.lastname@example.org
2) Federal Trade Commission: email@example.com
Additionally, you should file a complaint with the Internet Fraud Complaint Center of the FBI (www.ifccfbi.gov) and notify the company that has been victimized.
Mellody Hobson, president of Ariel Capital Management (arielmutualfunds.com) in Chicago, is Good Morning America's personal finance expert. Ariel associates Matthew Yale and Aimee Daley contributed to this report.