The new World of Warcraft Faction Change service is now live, according to Blizzard. Players will be able to change from Alliance to Horde or Horde to Alliance for a fee (30 dollars, and subject to taxation in some select states in the U.S.).

You can only change one character per transaction and only once every 60 days. Also, gold is limited according to the following table:

Level 10 to 30: 300 gold
Level 31 to 50: 1000 gold
Level 51 to 69: 5000 gold
Level 70 to 80: 20000 gold

For all info on the Faction change service, read FAQ Part 1 and Part 2.

Blizzard is also working on a new service that will allow players to change their race within their same faction and class. Additional details will be released at a future date.