#1 - June 21, 2012, 12:24 p.m.
You must be level 90 to participate in the raid test, and level 90 character templates will not initially be available. We do have some new technology that automatically raises or lowers your items to the appropriate level for testing. So as long as you have a Mists of Pandaria quest or dungeon item in every slot, you'll be fine.
Note that player interface add-ons are disabled on the beta at this time while we work through some technical issues. They'll be available once again at some point in the future.
As always with raid testing on beta or public test realms, the schedule is subject to change or cancellation with very little warning. Server issues, build issues, newly discovered encounter, combat, or class bugs, and many other reasons could prevent testing. While we will endeavor to provide warning about future tests, this will also not always be possible. Whatever we do know, we'll post here in the Beta Dungeons forum as soon as possible.
We're really looking forward to everyone's feedback (it really does matter!), and our thanks to everyone who's able to participate in the upcoming tests.
For the latest information about this, please keep your eyes on this US forum thread: http://us.battle.net/wow/en/forum/topic/5889160100