I read through the pastebin (the source is currently down) and I'm still not quite sure I get how Lulzsec did this. Could you (or someone) explain?

Heh, not sure how the pastebin got mixed up but I updated the post above. It was setting parent.location.href to the twitter account.

Thanks for updating! I've opened the new pastebin but still am not sure how it all worked together with the sun website to get it to redirect.

Do you happen to know how it got there? Though the pastebin does not show it.

That html page is normally included on the homepage as an iframe. The pastebin is entirely untelling of how it got there, but it is the source of the redirect.

That looks like it's an iframe that normally has no content but which can be updated by commenting in the sample bits to put a breaking news headline onto the homepage. Because the CMSes that run newspaper websites are often terribly crufty, people resort to workarounds like this.