The Horde doubtlessly doubles in size today, as players rush to join the winning team courtesy of Blizzard's newly-activated faction change service for World of Warcraft.
First announced back in June, the faction change service allows Alliance players to switch to the Horde side of things, choosing a new race on the opposing side and transferring over with all of their experience and equipment intact. The service runs $US30, and includes a makeover session so you can tailor your lovely new Horde character to your liking. Supposedly the system will also allow Horde characters to be transferred to the Alliance side, but why anyone in their right mind would do that is beyond me.
You can hit up the link below to read Blizzard's extensive, two-part FAQ on the process, covering everything from faction-specific equipment to the fate of your non-combat pets. I would have tried out the system myself, but apparently the account I've not accessed for months has been perma-banned for "intentional exploitation".
Faction Change FAQ Part 1 [Blizzard Support]