Old World of Warcraft raids Zul'Gurub and Zul'Aman are being reincarnated as level 85 heroic five-man dungeons.
They'll return in new patch 4.1, according to leaked notes on a Taiwanese website (correlated by MMO Champion).
Epic items of level 353 can be found in the new-style dungeons, and you'll need a minimum item level of 346 to enter them.
Zul'Aman's return heralds the reinstatement of the rare Raptor, Tiger and Warbear mounts.
Zul'Gurub was an evil troll-themed 20-man raid added to World of Warcraft in 2005 (patch 1.7), back when the top character level was 60. I remember fighting Hakkar the Soulflayer as he flapped menacingly up on that platform.
Zul'Aman was a 10-man raid for Burning Crusade's level 70s, added in patch 2.3.
Patch 4.1 will also apparently introduce a new Rallying Cry ability for warriors at level 83.
More to come, apparently.