Always jump to some "wpkg.org" site ?!!

Now whenever I open TSO's homepage it jumps to some "wpkg.org" website. This started about 3 hours ago. When I refreshed a frozen page expecting it would return to normal like always the jumping case first appeared.

I have cleared the browser cache, restarted my computer, maked sure the Flash version is up to date, looked for any virus evidence in the msconfig settings/regedit and found nothing. It seems that it only affects TSO's pages, I didnt encounter this problem at any other website so far. And I tried on IE, firefox and chrome, they all got this problem. What should I do now?

you have a redirect virus. Google wpkg.org virus removal to show you how to fix it :)

Thank you very much. How come I forgot about google?
Editing hosts file to block the site and using blocksite addon in firefox solved the problem for me for the time being.