I think we can get a lot of discussion out of these two topics from the Nintendo Power Aonuma interview. They're both new and very ambiguous, inviting many different paths of speculation.
This time around, the harp comes into Link’s hands during the course of the game and is used to help the player find something important. You actually need to play the harp to use it, so to speak. The design is the same as the harp that Sheik has in Ocarina of Time.
When I first read these, I thought they could be related, but I'm not really sure. Ocarina of Time 3D implies that the Triforce never left the Sacred Realm though not from lack of trying. As I said in the news post, I think they're going to surprise us with the Triforce's new role. I think the harp will have something to do with some Sheikah-related artifact, but it wouldn't be something we've seen before.This time around, the Triforce sort of takes on a different meaning and plays a different role in the story.