Blizzard Entertainment announced Monday a new expansion for its hugely successful World of Warcraft massively multiplayer online roleplaying game (MMO). The expansion, Wrath of the Lich King, will boost the level cap for the characters to level 80, introduce new classes, professions, character customization options, and a new continent.

Wrath of the Lich King moves the story to Northrend, where the Lich King introduced in Warcraft III is plotting world domination. According to the back story information posted on the WotLK Web site, Northrend will introduce new NPC races and story arcs centered around the Lich King.

The company has not announced pricing or the release date for the expansion pack, but the previous expansion, The Burning Crusade, was released in January of 2007, some six months after it was announced.

While details are sparse, the company did offer a bullet list of new features:

• Master the necromantic powers of the Death Knight - World of Warcraftis first Hero class.
• Quest to level 80, gaining potent new abilities and talents along the way.
• Learn the craft of spell augmentation with the new Inscription profession.
• Brave the harsh new continent of Northrend, the icy domain of the Lich King.
• Engage in epic siege warfare, deploying mighty siege engines to lay waste to destructible buildings in your path.
• Transform your herois look with new character-customization options, including new hairstyles and dances.
• Explore perilous new dungeons filled with some of the deadliest creatures -- and greatest treasures -- on Azeroth.
• And much, much more...

You can find more information in the "back story" links on the WotLK Web site. There is also a trailer for the game, though the current Safari 3 beta was unable to display it (Firefox displayed it without issue).