The Oscars is set to take place on Sunday, February 27th, 2011.
Nothing official about this, we know how IMDb works.
The Official Twitter of the Academy who has been announcing presenters and updates has not twitted anything about Rob being a presenter. And the actors that were officially announced here like Nicole Kidman, Jude Law, Tom Hanks, Annette Bening, Robert Downey, Jr. among others, were NOT listed above. So take this with a grain of salt. This is labelled rumor for now.