Users of Microsoft's Internet Explorer Web browser will not have to wait until IE7 to experience tabbed browsing. MSN has shipped a new build of its MSN Search Toolbar that adds basic tabbed browsing support to IE6. But the feature is not fully integrated into the browser, instead relying on the toolbar to create tabs.
http://desktop.msn.com/default_desktop.aspx?patch=yes
It's a little buggy 'cause it's not fully integrated into the browser but it works.
If you prefer Google over MSN Search stick this into your search options:
http://www.google.com.au/search?hl=en&q=$w