Patch Notes for the Phase4 test:
http://forum.square-enix.com/ARR-Test/threads/98689-Beta-Test-Phase-4-Patch-Notes?p=1211637#post1211637

Schedule and Details for Phase 4:
http://forum.square-enix.com/ARR-Test/threads/98692-Beta-Test-Phase-4-Schedule-and-Testing-Details

Dates and Times
Saturday, August 17, 2:00 a.m. to Monday, August 19, 2:00 a.m. (PDT)
Saturday, August 17, 9:00 a.m. to Monday, August 19, 9:00 a.m. (GMT)

However, users who fulfill any of the following requirements are eligible to participate starting from Friday, August 16, at 2:00 a.m. (PDT) / 9:00 a.m. (GMT):
Played Version 1.0
Legacy Campaign members
Registered a Beta Test registration code by Tuesday, July 30, 2013 9:59 p.m. (PDT) / Wednesday, July 31, 2013 4:59 a.m. (GMT)
Received a PlayStation 3 promotion code in the days before the start of Beta 4 testing

Seems like Gilgamesh is going to be really over populated and there are going to be a ton of communities there. Now we can just powerman 5000 through it or decide to pick up a different banner and go somewhere else. If you have any suggestions that would be wonderful.

Here is the unofficial list so far of communities playing the game.
http://www.reddit.com/r/ffxiv/comments/1kby3t/officialunofficial_servers_for_different_online/

Ultros was my second choice but I am open to suggestions.
http://strawpoll.me/333994