...It's almost exactly the same as our old, "lesser" MacBook Unibody.
The battery compartment is identical to the one we uncovered in the MacBook Pro 17" Teardown. We'll venture a guess that it looks the same in the updated 15" Pro as well.
Remove two tri-wing screws and the battery is suddenly replaceable. The sticker comes right off, just as in the 17" Pro -- because it's adhered to just the battery and midwall, not to the optical drive.