In the Finder, open Navigator.app (control-click and "Show Package Contents") and then navigate to Contents -> Resources -> WebsiteDefaults.strings and open it in your favorite pure text editor (I use BBEdit). Change SearchPageDefault = "http://www.dmoz.org"; to whatever search page you would like to use.
Now, when you click on the search button, it will go to that page. Now you have yet another reason to use Chimera!

