Recently a huge PvP battle took place on the Korean closed beta servers. Blizzard posted coverage of it today on their site. Here's a brief clip from the article.

A Rumble in the Desert
The armies of the Horde and the Alliance in the Korean World of Warcraft closed beta test gathered for war on the sands of Tanaris. In a mighty clash involving myriad players on each side, the factions battled. The Alliance fought bravely but was no match for the fearsome might of the Horde. Badly beaten, the Alliance slinked away from Tanaris and inevitable doom.

For the complete article visit the WoW Beta site here.