The Order of the Phoenix is a secret organization founded by Albus Dumbledore in the late 1950s. Though originally only intended as an information network to track the movements of Lord Voldemort upon his return to the country, the Order evolved into a vigilante force with members dedicating to eradicating the Dark Lord and his followers. Though the Order comprises some very talented witches and wizards (among them Albus Dumbledore), their morality and hesitation to use unforgivables puts them at a disadvantage in confrontations with death eaters. However, their secrecy and ability to operate outside the law has made the Order far more efficient in circumventing the Dark Lord's plans than the auror department, and as such they have been given the ministry's unofficial support during the war.
Members of the Order range from aurors to criminals to the terminally unemployed, and though there are few 'requirements' necessary to join, most members have been handpicked for their goodness of heart, pure motives, and ability to put up with Aberforth's smell.
As of 1979, the Order of the Phoenix remains secret; though there have been media mentions of 'vigilantes' and the Ministry quietly acknowledges there are those who act against Death Eaters outside of the law, there is little to no knowledge about the 'group' itself. As loyalties shift and make themselves evident, this may very well change.
members
These are the canon members that will make up the Order at the outset of the game; other characters are free to join as new recruits, but remember that you cannot play two characters in the same organization - so if you already have an Order member, your auror cannot later join the Order as well.
Sirius Black
Edgar Bones
Caradoc Dearborn
Dedalus Diggle
Elphias Doge
Aberforth Dumbledore
Albus Dumbledore
Benjy Fenwick
Alice Longbottom
Frank Longbottom
Remus John Lupin
Marlene McKinnon
Dorcas Meadowes
Alastor Moody
Peter Pettigrew
Sturgis Podmore
James Potter
Lily Potter
Fabian Prewett
Gideon Prewett
Emmeline Vance
projects
The Order doesn't have the same level of organization as does the Death Eaters; there is no hierarchy and while all Order members are expected to respect each other, the only person to whom everyone defers is Dumbledore. However, there are various 'projects' to which members can contribute time, loosely defined as they are.
surveillance
One of the Order's age old tasks - surveillance - is as important now as ever it was. Though Death Eaters aren't always easy to track down, keeping an eye on them is the best (and sometimes only) way to anticipate their movements and protect innocents from harm.
reconnaissance
It's a dangerous job, but someone's got to do it. Though certainly more risky than rote surveillance, reconnaissance work is ultimately more useful to the Order. There are very few members daring (and anonymous) enough to actually infiltrate into the network of Death Eaters, and those who do risk discovery, torture, and death.
training
Not everyone's ready (or willing) to take a dark wizard head-on in combat, and it is the job of the Order trainers to help new recruits (and some older ones) improve their wandwork and even the playing ground. Some Order members also have taken on the responsibility of helping the innocent bystanders of the wizarding world brush up on their defensive spells.
propaganda
Like any organization devoted heart and soul to a cause, the Order has members dedicated to spreading the word about the Order's mission, and those they have sworn to fight. Whether through print, radio, or public activism, propagandists play an important (and very dangerous) role in the war. Note that the Order is not a 'public' organization and all propaganda will be devoted to spreading the word about the cause and the truths about those they oppose - not the organization itself.
combat
Like it or not, the wizarding world is in the midst of a war, and anyone, anywhere, may find themselves confronted by violence without warning. There are those who are more ready and willing to engage in direct combat with the enemy, however, and these 'army reserves' have to be prepared to apparate to battle at a moment's notice.
watch-guard
With the Ministry's reticence to acknowledge the Death Eater organization, the Order of the Phoenix has placed Order members in strategic wizarding locations as 'guards' to stay on the alert for Death Eater activity, and to raise the alarm during attacks. Though the Ministry did eventually acknowledge the terrorist threat publicly, their protection of wizarding towns has been minimal at best; the Order continues to act as a buffer between dark wizards and innocent civilians.
recruitment
Though not an 'army' by any means, the Order is an organization devoted to battling Death Eaters - and organizations devoted to battle are frequently in need of new recruits. There is no special recruitment process, and if the current cast is any indication, there are also no prerequisites for joining. All members are personally recruited by current members, however, and though they aren't required to have any special talents, their trueness of heart is what will ensure them admittance.