Jimmy Hart said that in good confidence like two or three weeks ago or something. It hasn't been confirmed just yet (although it obviously will be.)
Anyone who knows anything about wrestling or WWF history will understand the significance of having Hulk Hogan at least make an appearance at the milestone Wrestlemania event this year. I don't care how old he is or how much space you think he'll take up or even how often he hogged up television time in TNA (which is especially irrelevant since that's a whole other company and 99.9% of WWE fans don't watch TNA... in their minds, Hogan is a returning hero who hasn't be seen in WWE since 2006), he's the guy who first made the WWF into a monster and helped make Wrestlemania into the spectacle that it is. It's only fitting he have some type of role at this year's Mania. I'm fine with just about anything he does as long as he doesn't step into the ring for another match. A tag match with Cena would be passable, but I'd rather not see that either.