SOE has some middle of the night downtime planned.  According to a post on the Station.com forums:

From 4:00 AM PDT until 6:00 AM PDT on Thursday, June 11, 2009, we will be conducting back-end maintenance that will affect the in-game chat and mail systems for SWG, EQ2, and possibly EQ.  SWG and MXO worlds will be offline entirely for the 2-hour duration.

 

We apologize for this interruption and will resume all affected services as soon as the maintenance is completed.

Here's a handy time converter to help you plan!