All SOE game servers will be offline for hardware maintenance beginning at 1:00 AM PST on Thursday, December 10, 2009. This includes all SOE MMOs as well as TCGs. The downtime is expected to last around 5 hours.

For EverQuest II servers the downtime will last until 10am PST, for a total of 9 hours estimated downtime.  This extended downtime will be for all EQII servers so that hotfixes and Frostfell can go live.

Here's our time zone conversion tool to help you plan.

This information changed since it was originally posted; the above is our most current info.

source: EQII Forums