SOE has provided us with very little information. Not even a daily, "EQ will not be up today" message. One wonders what the PR people as SOE do all day, it sure isn't keeping us in the loop.
SOE has created a Recent Updates page which should help.
UPDATE: SOE has belatedly begun to post "EQ will not be up today" messages on their Facebook page.
UPDATE: With very little information coming from SOE, rumors are everywhere and facts are almost nowhere to be found. The EQ2 Wire seems to be the best place to find out what is going on, since SOE has never understood the word "communication" (hint: try dictionary.com :).
From The EQ2 Wire we hear that Bloomberg.com reports, "The company is in the process of adopting an improved security system and its plan to restart the services fully by May 31 is unchanged".
Naturally, they are talking mostly about the PlayStation Network, since that is where Sony makes the most money. SOE (EverQuest) is just an afterthought.
UPDATE: Industry Gamers has posted a letter they claim was sent to Sony's publishing and development partners about the hack.