IMDB sucks. They get so much information wrong, AND late.
I doubt very much they'd go to great lenghts to get Orlando Bloom to voice Will Turner, however, I would hope they'd TRY to get Johnny Depp to voice Sparrow, and Kiria Knightly (did I spell that right?) for... um... whatever her name was.
The problem is, those are some BIG names. Hell, they couldn't even get Danny DeVito for Phil in the first game (and I'm not so sure they'll get him for the second), and you can see how many hits HE'S done lately. But that's okay. Some sound a likes work fine, just like Phil's. However, some voices you just NEED the original actor.
I'm somewhat disapointed that they didn't get Robbin Williams for the genie, but not anywhere near suprised. For the next game, I really hope they can get Eddie Murphy for Mushu. I think his voice is unique enough that people will be able to tell the difference. He's not just a summon in this game, and Eddie Murphy can't be THAT expensive to get.
So um... Original point basically: Orlando Bloom is VERY unlikely. But hopefully they'll (somehow) get Johnny Depp. No one else can fit the Sparrow role like him.