window.parent.location.href = 'http://yoururl.com';

[eluser]xwero[/eluser]
If you are talking about going to the landing page of the site using redirect just add an empty string.

If you are talking about closing the lightbox it is bad form to use location.href because the idea now is to use javascript to emulate desktop software UIs that don't reload their interface when changes are made. A better way to do it is to hide/remove the overlaying elements.