NOTE: anti-virus software is basically worthless unless it is kept up-to-date with the latest virus definitions.
Many of the sites below will offer immediate information on viruses, hoaxes, and their impact.
Understanding Anti-Virus Software
Cyber Security Alerts from The United States Computer Emergency Readiness Team (US-CERT) provide timely information about current security issues, vulnerabilities, and exploits. They outline the steps and actions that non-technical home and corporate computer users can take to protect themselves from attack.
Cyber Security Tips describe and offer advice about common security issues.
The CERT® Coordination Center (CERT/CC) is also a center of Internet security expertise.
Virus information from Symantec (Norton), or McAfee.com which also offers a variety of current information including hoaxes and world maps of virus attacks.
E-mail attachments are a major source of viruses. Do not open suspicious attachments, simply delete the e-mail (and empty the trash).