This has been added as an ingame q on 25/10/2008 for the (new) Scourge invasion.
It can be obtained from an Argent Scout in any of your factions capital cities. This q requires you to travel to Light's Hope Chapel in the Eastern Plaguelands and speak with the Keeper of the Rolls.
Scourge invasion info: (wowwiki)
Zombie Infestation - Return of the Scourge Invasion On Oct. 22, 2008, Healers from the Argent Dawn posted themselves in key positions in all cities across Azeroth, anticipating that a new invasion was on the rise. This would prove to be a wise decision, as the invasion did not take the form of necropoli and undead cannon fodder, but aimed mostly at the far-traveled adventurers that were instrumental in the defeat of the first invasion.
Mysteriously appearing Conspicuous Crates would come to peak the curiosity of some hero, who would open them only to be infected with a fast-acting Zombie Plague. On October 23, Plagued Roaches began to appear in the capital cities; killing them would release a plague cloud and infect the attacker, even if he or she struck from a distance.
Should the infected person not be able to recieve treatment in 10 minutes time from the Argent Healers or a fellow adventurer trained in treating disease, they will transform into a Plague Zombie. Not only does this new Undead add to the Scouge's ranks as a warrior, but is also capable of infecting others with the very same disease that turned him or her. It has been observed that healing from sources other than the Argent Dawn agents is becoming less and less successful with the passing of time, often requiring numerous attempts to remove the plague infection; this indicates the plague is becoming stronger and more resistant, leaving adventurers with only the Argent Healers as their safest and surest method for escaping undeath as a Plague Zombie.
Only time will tell if the heroes of the world will once again turn back the Lich King's new attack... or become a part of it.
Event announcement from the World of Warcraft Forums: http://forums.worldofwarcraft.com/thread.html?topicId=11693660644&sid=1&pageNo=1
Have fun while you ca... BRAAAAAAAAIINNSSS...
*Lich King*: Muahahahahahaha...