The team over at WoW WarCry has two plenty good intros, so I'll just repost them here:

TrustedReviews just got done writing up a preview on the Burning Crusade, the expansion to the popular game called World Of Warcraft. Their review is 4 pages long and chock full of new screenshots. So why not head on over and take a look around.

Unsurprisingly, Blizzard is well aware of the frustration that these high-level players feel and has come up with the solution - The Burning Crusade. I first got my paws on The Burning Crusade back in May, when I flew out to Los Angeles for E3. But last week Blizzard invited me along to a hotel in London to see how its WoW expansion pack was shaping up. Burning Crusade has definitely moved on since I saw it a few months ago, and hopefully Blizzard will be able to hit its pre-Christmas release date in December. But what should you expect from this first expansion to, quite possibly, the most widely revered Massively Multiplayer Online game out there (cue hate emails from Eve Online players)?

But it's trusted Reviews, not trusted Previews! I call shenanigans.

The next preview comes from a site called Bit-Tech. And they are covering the new races, new locations and new features. This article also has a bunch of colorful screens.

Previewing an expansion pack for an MMO is a difficult task, as the major criteria for deciding how great it will be rests on how good it is when placed in that massively multiplayer environment. We found it slightly underwhelming checking out these new lands with only three other snotty-nosed games journalists there to play with.

That being said the game still manages to maintain an aura of excellence. Despite the engine being a few years old now, certain scenes are breathtaking. Although I am worried about the integration of the new races, the only possible pitfall I can see for the game; I am encouraged by Blizzard's enthusiasm in providing lore to explain everything. As far as the changes to dungeon game play go, things look positive. Even the lowering of the raid party sizes should make raiding a more accessible element. Of course, there will be those up in arms about any changes to their beloved game, but thankfully - due to Blizzard's history of churning out top notch games - those doubters are few and far between. Keep your eyes peeled for Burning Crusade, due for release sometime in December.

A big thanks to Tsurani for posting these initially. In the immortal words of Sean Connery, Yes.... YES!

Something like that.