Nope. No UP 3D Release Today
The popular film has been available on 3D blu-ray in many European countries as early as January of this year, but still hasn't seen the light of day in the US, save for a few foreign imports that are asking quite the pretty penny on Amazon.
Despite that, a Spring/Summer 2012 release does not seem improbable. I'd be surprised to see it delayed clear until their standard early November blu-ray release days when Brave will likely be released. In the last couple of years, Pixar has made something of a fanfare of their home video release days, often releasing several of their titles at once.
I'm glad I tacked a question mark to the end of my original article!
UPDATE: UP 3D was not released on blu-ray last May, but is coming December 2012.