You’d need to manually add some attributes to your links like that:
a href="http://www.google.com?iframe=true&width=100%&height=100%" rel="lightbox" title="Google.com opened at 100%">Google.com
a href="http://www.apple.com?iframe=true&width=500&height=250" rel="lightbox">Apple.com
a href="http://www.twitter.com?iframe=true&width=400&height=200" rel="lightbox">Twitter.com
