SPOILER WARNING! If you are one of the three people left who regularly reads Superman comics on a monthly basis, you should stop reading immediately.
Seriously: This is your last warning.
Okay. According to Comics Alliance, Superman renounces his U.S. citizenship in a short story in today’s Action Comics #900. Here’s the relevant panel:

If the right-wing blogs get a hold of this one, there’s gonna be hell to pay, especially when somebody realizes that David Goyer, who wrote the story, is also the screenwriter of the upcoming Superman movie directed by Zach Snyder and starring a British person as Superman. So they’re neutering America’s greatest superhero and turning him into a thug for the United Nations? This could make the Captain America mess look tame in comparison.

Supes was just pissed because they kept bugging him about his birth certificate.
Next up Superman tries weed and realizes how groovy being stoned is.
Love it. I’d buy that comic.
Clearly, Iron Man was right. We need a Superhuman Registration Act NOW.
The Captain America thing always makes me smirk. You know, a New Dealer fighting for FDR’s America would have no opinions about the Tea Party at all.
Right-wing bloggers should just accept that Superman is a dick. There’s a whole website documenting it.
Superman is an illegal immigrant after all.
how do we know he was really born on krypton? have we seen a birth certificate?
It was another boring issue from a company out of ideas, and desperate for attention. No wonder their sales are tanking.