So apparently inside the Utgarde Catacombs (which is probably the lower section of Utgarde Keep-- I played the upper section), there is a cleric of the Silver Hand, the group led by Tirion Fordring that fought against the Scourge in Naxx, as well as other places. The cleric sends you on a timed quest inside the dungeon, to retrive a "Sacred Artifact." After you retrieve it, he sends you with his dying breath to someone back in town, who then tells you that the Artifact you just held in your hands is related to the Ashbringer, thanks you for grabbing it, and takes it away (as, Boubouille says, "the ret paladin of your party keeps crying"), promising to give it to Fordring in his fight against Arthas. How is it related to Ashbringer? Well, it could be the blade itself, except that the Corrupted Ashbringer was last seen in player hands, not at the bottom of a dungeon. Most likely, it's a mirror, or a copy, of the artifact seen in Old Hillsbrad-- a new holy artifact, meant to create a new, uncorrupted Ashbringer.
So that's kind of cool. It definitely shows how Blizzard is going to make good on their promise of involving us in the lore right away when you enter Northrend-- at BlizzCon, they said a few times that most players worried they would never see Illidan, so the idea with WotLK is to bring the lore to you (we're supposed to meet Arthas early on in this way as well). I like the way this is done-- even though you don't get to wield it, you're still able to interact with it. Should be very exciting to see how Blizzard incorporates other parts of the lore in this way.
Just so we don't take down MMO Champion's site with hotlinks, I've mirrored the three quest images after the jump.
Update: MMO Champion got it from Cydel, who also has video.