If the amount of time being taken is any indication, Square Enix is being very careful and deliberate with the planned relaunch of Final Fantasy XIV. The company still hasn't given an official launch date, but signups for the beta have begun right now.
According to a roadmap (PDF) discovered by NeoGAF (via Eurogamer), the beta will be deployed in four phases. American gamers will have to wait until phase 3, as detailed on the roadmap and on Square's US beta page. The beta starts in mid-February in Japan, and then could take anywhere from 7-18 weeks to complete the rest of its tests. The third phase is estimated to come in late March at the earliest.
The fourth and final phase will include PS3, and characters created during it will be carried into the final game. The level cap will be set at 35 in all but the final phase, and all genders and races will be playable from the very first beta sessions. More worlds will open progressively, from 5-10 at the start to more than 20 by the final phase. The game is now accepting beta sign-ups.
The time frame given means that the full launch could be as soon as spring, but that's optimistic. The latest release date in Square's estimates put it at late June. All of this could change based on testing and feedback, though, especially given that the new game director felt the company made a mistake by not holding off after a poor beta the first time.