From the blue post:
You can use:
Any item below item level 245.
The item level 245 set pieces that drop from 25-player Trial of the Crusader but also appear in the 10-player Tribute Chest.
Any gear that drops in 10-player Trial of the Crusader or Trial of the Grand Crusader, including item level 245 Trial of the Grand Crusader drops and item level 258 cloaks from the 10-player Tribute Chest
Any item level 245 items purchased with [Badges of Triumph].
Any item level 245 Bind on Equip item, including crafted pieces.
You cannot use:
Any item level 245 item not included above (primarily Bind on Pickup drops from 25-player Trial of the Crusader, but also notably [Val'anyr]).
Any item over item level 245 except for the 10-player Tribute cloak.
Any higher item level loot introduced in future patches (25 player Onyxia 245s, Icecrown loot in the future, etc.)
For Herald:
All loot from Ulduar 10-player, including loot from hard-modes and from Yogg-Saron.
Any 226 item level loot from Ulduar 25-player, Tier 8 pieces, or PvP gear.
Weapons (shield, offhand, ranged, etc.) can be 232 item level - including loot from 10-player Onyxia's Lair, Trial of the Crusader, and the Heroic ICC 5-mans: Forge of Souls, Pit of Saron, and The Halls of Reflection.
Sigils, Librams, Totems, and Idols can only be 226 or lower item level.