Web of Trust (WOT) - IE, Firefox, Chrome, Safari
http://www.mywot.com/
Browser Defender - IE, Firefox
http://www.browserdefender.com/
McAfee SiteAdvisor - IE, Firefox
www.siteadvisor.com/
(P.S. Do not install Browser Defender and McAfee SiteAdvisor at the same time, as they do confict with each other .)
Remember, search up a website first BEFORE you click on the link. These are not Anti-Virus software, but only website notifiers.