Amanda "Amary" Fry posted on the official forums that the NA region shards will be coming down for the update to 1.4 tomorrow morning, 8/3/11, at 8:00am PDT. The estimated downtime is 1 hour.
Patch notes will be posted as soon as they are available. In the meantime you might enjoy a glance at the Planar Menace event guide and Hammerknell Fortress page we've been working on!
All that stuff is from Test and whatnot, so don't be shy about contributing!