Here is a great Firefox Extension that will keep you informed about suspicious sites by McAfee called SiteAdvisor. It works with both Google and Yahoo!’s search engines. If don’t know what Extensions are take a look at Wikipedia‘s entry.
There are many suspicious sites out there pretending to be legitimate ones through copied content but contain dubious links and other . By analysizing its pop-up, link information and emailing policy SiteAdvisor shows you if the site is safe (a green tick), questionable (a question mark) or unsafe (an exclamation mark or red cross) so you can decide whether you want to visit the site or not.
I also recommend Mozilla’s Firefox browser (over Internet Explorer) for better internet security and experience.