all EverQuest is having an emergency patch at 6:00am on Wednesday, September 21st. Downtime is expected to be two hours.All times should be assumed to be Pacific time (USA).
UPDATE: SOE has posted the full information on their forum:
All EverQuest Live Servers will be coming down on Wednesday, September 21, 2011 at 6:00 am US Pacific (US Pacifc [sic] -PST is -8 GMT: 5:00 am MST, 8:00 am CST, 9:00 am EST, 2:00 pm GMT, 3:00 pm CET) for a game update. The servers are estimated to be unavailable for 2 hours. Keep an eye on the EQ Players website and the forums for status updates and for news if additional downtime is needed.