You can still read it. You have to drag your mouse cursor over the text so it "Selects" the text. It is just Black Text on a Back Background. Highlighting it makes the text the opposite color.
Also, Wikipedia has gone into blackout mode as well.
Heh. It's supposed to be annoying and make users question "what would the Internet be without this information?" English Wikipedia currently uses JS to prevent people from reading articles. In a pinch, you can try hitting the "stop loading" button on your browser after an article loads, but before the screen changes -- or just disable JavaScript on your browser. Even Google's changed their logo specifically for this political message, which is unprecedented AFAIK.
Firefox with noscript and adblock makes wiki load normal.
I don't see a single message about SOPA anywhere, accept for at the top the Ron Paul Forums (becuase I allow all of this page).
In a pinch, you can try hitting the "stop loading" button on your browser after an article loads, but before the screen changes -- or just disable JavaScript on your browser.