This article or section is likely to dramatically change once the Cataclysm begins.
Feel free to update any incorrect values (e.g. ability and talent articles), but please avoid overwriting all previous information with more current information (e.g. location and NPC articles).
According to the quest [80] Tirion's Help, Tirion Fordring handpicked every paladin member in the Argent Crusade in order to avoid infiltration by the Cult of the Damned. This was presumably to prevent a repeat of the Inigo Montoy incident, which resulted in Naxxramas returning to Northrend and Kel'Thuzad regaining corporeal form.
It should be noted that, despite the new Tabard the Argent Crusade uses, several of their members can be found using the old tabard of the Argent Dawn (this is referring to members of the Argent Crusade faction in Northrend, not the Argent Dawn members who are found in Eastern Kingdoms/Kalimdor). Those who wear the old tabard range from the common infantry to the commanders and senior members of the Crusade. This may mean that the two tabards are interchangable in the Crusade, and the old Argent Dawn tabard may still be in production as part of uniform for the members of the Crusade. Avenger Metz, for example, still uses the Argent Dawn tabard instead of the newer Argent Crusade one.
The main front-line encampment of the Argent Crusade appears to be at the Argent Vanguard, on the border between the Storm Peaks and Icecrown. A few other camps include:
[76 Daily] Congratulations! (if Troll Patrol was completed quickly enough - within 20 minutes) (650 reputation)
Reputation can also be gained by purchasing [Tabard of the Argent Crusade]1 from Aliocha Segard in the Argent Vanguard. This tabard, while worn in level 80 dungeons, awards 2 to 30 reputation per mob depending on its difficulty and 300 reputation per boss to your standing with the Argent Crusade.
This section concerns content exclusive to Cataclysm.
In World of Warcraft: Cataclysm, the Argent Crusade will strengthen its presence in the Plaguelands, claiming not only outposts formerly held by the now-defunct Argent Dawn (such as Light's Hope Chapel), but also the former Scarlet Crusade town of Hearthglen, and the four towers through the Eastern Plaguelands, around which the plague has receded.
There are quests available which give Argent Crusade reputation originating both from Hearthglen and from the nearby Northridge Lumber Camp, which was also reclaimed from the Scarlet Crusade.