Well, they're not in the Player's Handbook. I'd hope to have them available on DDi pretty soon after the PH hits, though, since players out there with half-orc characters are going to want to be able to convert or re-create their character concept, as the case may be.

Half-orcs are a bit tricky, because they imply a very ugly backstory that we frankly don't want to dwell on very much. I think it's possible to posit a better backstory, like "long ago a god of evil mixed the races of orcs and humans, and to this day atavistic throwbacks are born to each from time to time." We'll see where we get to on that score when we get serious about updating the half-orc. So far we've just had other fish to fry first.

Oh, and regardless of what core D&D does with half-orcs, they've got to be in the Realms at least as a NPC race (or "playable monster" race); they've been in Faerun in 3e and earlier editions, and we wouldn't retcon them out of existence.