Here is a handy tool bar, yes one thats actually useful, unlike search engine tool bars. McAfee SiteAdvisor is a tool bar that attempts to offer protection from Adware, Spam, Viruses, and Online Scams.

Features:

• When you search with Google, Yahoo! or MSN, SiteAdvisor’s safety ratings appear next to search results.
• As you browse, a small button on your browser toolbar changes color based on SiteAdvisor’s safety results.
• Menu options on SiteAdvisor’s toolbar let you customize SiteAdvisor or see a site’s detailed test results.

Not to mention it works in Firefox and Internet Explorer.