In a very convoluted bit of reasoning with full disclaimers:

WoW Insider received information from an anonymous tipster that the Video Games Live orchestra will be performing three pieces called “Northrend 1, 2,and 3″ at next week’s BlizzCon. WoW Insider dug deeper and found the track names do not appear on Warcraft II, Warcraft III, World of Warcraft or the Burning Crusade soundtracks. This could mean the continent of Northrend will finally come into play in the next expansion and gamers will be able to take on Warcraft III’s anti-hero/villain (depending on your perspective), the fallen Prince Arthas, who now sits on The Frozen Throne.

Read the details HereSource: Joystiq