Incorrectly reported here as part of the new Veil of Alaris expansion, the Security Tokens are currently live on all SOE games.
They were given free to all Fan Faire attendees. It seems anyone else who wishes one will have to pay SOE for it.
Security Tokens work by creating a number which is synchronized with the game servers. Upon logging in, you are asked to provide the number in addition to your normal password. The number is different every time you log in and is displayed on the token, which is a small key fob. Anyone attempting to log into the account will be unable to do so without the number. This will be optional for those who want extra security.
Details will hopefully be announced soon.