References:

US-CERT Securing Web Browser Information
http://www.us-cert.gov/reading_room/securing_browser/browser_security.html

Internet Explorer 7 Desktop Security Guide
http://www.microsoft.com/downloads/details.aspx?FamilyID=6AA4C1DA-6021-468E-A8CF-AF4AFE4C84B2&displaylang=en

Microsoft Internet Explorer Weblog
http://blogs.msdn.com/ie/

Mozilla Security Center
http://www.mozilla.org/security/

Firefox Vulnerabilities
http://www.mozilla.org/projects/security/known-vulnerabilities.html

@Risk: The Consensus Security Alert
https://www.sans.org/newsletters/risk/

Read more: http://www.sans.org/top20/