Kiara posted on the EverQuest II Forums about a planned 12 hour downtime next week:

There will be maintenance on the Session databases across all games on Wednesday September 9, 2009.  It will begin at 12AM PDT and is estimated to last until 12PM PDT.  All game worlds will be unavailable for the estimated 12 hour maintenance, as well as the Station Store and all commerce avenues.  This may affect the performance of the forums and any or all accounts’ abilities to log in.

We apologize for the inconvenience and will update the information as we are able.

SOE Community will be providing updates via Twitter during this down time.  Click here for links to SOE Community Twitter information.