According to this WorldofWar story, Achievements are definitely going to be added to World of Warcraft, as Blizzard has now confirmed.
"While Wrath of the Lich King will improve many of World of Warcraft’s existing features, it will also introduce plenty of brand-new ones to keep the game fresh and interesting," said the company in a blog post.
"One of these new features is sure to suit a wide range of play styles: achievements. These self-contained goals will offer new challenges, satisfy goal-oriented players, allow others to see your accomplishments in World of Warcraft - and are just plain fun."
All details through the link.