While the closed beta servers were named for the bosses of the Final Fantasy series, the open beta servers (and the assumed launch servers) are named for famous cities from the games. This beta also had changed the previously homogenized stats of the races to differentiate racial choices -- but with the differences only being a few points in any direction, there's no huge impediment to playing any class as any race. Take a look at the full patch notes for a rundown of changes if you were in the prior beta, and keep trying if you find your registration attempts getting disconnected. Apparently there's no shortage of eager Final Fantasy XIV fans.
Update: Square-Enix has posted an official message on the account page advising players that the servers are heavily congested, and that if you're having any technical troubles to please wait and try back later. Codes are currently being limited in an effort to fight server congestion. The full statement is after the break.
"We would like to take this opportunity to provide an update regarding the congestion of the Square Enix Account Management System.
Due to heavy server traffic, we are continuing to experience Square Enix Account Management System congestion. Currently, players may not be able to log into the FINAL FANTASY XIV Open Beta Test, or acquire registration codes for the game.
Our technical staff is monitoring the situation closely and working to resolve this issue. As a countermeasure to the congestion, we are currently limiting the acquisition of registration codes for the Open Beta Test. If you cannot acquire a registration code, or if you are unable to access the Square Enix Account Management System, we ask that you please wait and try again later.
We apologize for any inconvenience."