The Sunwell Plateau dungeon is nearing after patch 2.3 and will make it to PTR very soon.  So what does that mean?  Sunwell Plateau is to be the last content patch dungeon of the Burning Crusade giving path to … oh yea,  Wrath of the Lich King expansion.  Strangely, very few details have been said about the new expansion since Blizzcon, and no mention of closed beta has been made.  At least we have the certainty that Sunwell Plateau might be here before christmas?—This is what Tigole said:

Tigole: Sunwell is coming along nicely. It will be on the PTR shortly after 2.3 goes to the live realms. We still need to perfect 2.3 a bit on the PTR.

The 5 person dungeon is complete and the 25 person raid instance is progressing nicely. There’s also a cool “public” area featuring brand new daily quests called Sunwell Isle.