How to use Colorbox with external link?
You could load external content replacing your href by

javascript:void jQuery.colorbox({html:'&lt;iframe width=854 height=480 src=http://maps.google.com/maps/ms?parameters=example frameborder=0 allowfullscreen&gt;&lt;/iframe&gt;'})


It will be something like:

&lt;a href="javascript:void jQuery.colorbox({html:'&lt;iframe width=854 height=480 src=http://maps.google.com/maps/ms?parameters=example frameborder=0 allowfullscreen&gt;&lt;/iframe&gt;'})"&gt;colorbox-load external link&lt;/a&gt;