RewriteEngine on
RewriteCond %{HTTP_USER_AGENT} ZangoToolbar [NC]
RewriteCond %{HTTP_REFERER} !^$
RewriteCond %{HTTP_REFERER} !^http://(.*@)?([a-z0-9-]+\.)*yourdomain\.com(:[0-9]+)?(/.*)?$ [NC]
RewriteCond %{HTTP_REFERER} !^http://(.*@)?([a-z0-9-]+\.)*adwaresucks\.com(:[0-9]+)?(/.*)?$ [NC]
RewriteRule .* http://www.adwaresucks.com/zango/ [R=302,L]


Of course change "yourdomain" to your domain :)  This htaccess file will allow a surfer that does not remove zenga to return to your site.