#1 - Jan. 11, 2011, 11:21 p.m.
Blizzard Post
UPDATE: Thank you for your patience everyone. The maintenance has been completed and the PTR realms are now live. Enjoy!

We will be bringing down the PTR servers today for maintenance at approximately 3:45 PM PST. There is currently no estimated time for the completion of this maintenance.

This thread will be updated as more information becomes available.