CustomizeGoogle

"CustomizeGoogle is a Firefox extension that enhances Google search results by adding extra information (like links to Yahoo, Ask Jeeves, MSN etc) and removing unwanted information (like ads and spam)."

Good extension to anonymize yourself in the face of Google's tracking machine.

There is also an Internet Explorer version available here.

To prevent cookies from being set for Google Analytics
Google Analytics is used by Sponsored Communities to keep track of visitors.

"CustomizeGoogle Options" is in the Tools menu of Firefox. Go to the Privacy tab of the options and check "Don't send any cookies to Google Analytics".