I'll try to explain the strat my guild uses as best as possible. (I submitted a screenshot to accompany, hopefully it gets approved - Until then - Here is a link to the strat image hosted on another site --
http://i7.tinypic.com/34fl3ko.jpg)
You'll want a 'lock with *some* arcane resist - it doesn't have to be much - but it helps the healers out a little bit. Other than that, nobody needs even the first shred of arcane resist.
After you've cleared the room and are preparing for Curator - enter the room and stand against the wall to the right (as you enter) - Its good to line up along that wall and have everyone ready to get into position. Curator has a HUGE aggro radius so buff up here.
Don't worry about curator heading your way, if your against the wall your JUST out of reach. - The area where he stops, and turns around is where you will want to tank him - facing the group
When you engage him, you'll want 1 dedicated healer on the tank, someone who is mana efficient and is prepared to pop pots every time they're up. Have that healer run up with the tank, and stand to one of the sides of Curator. Your other 2 healers should stay against the 'back wall' and spread themselves out.
Your ranged DPS should split up into 2 groups - Typically we have 4 ranged dps so we put 2 on either 'side' of the room. - 2 at the entrance doorway, and 2 directly across from it. Have your lock move forward enough to curator that he's maybe 20 yards from the tank. (You want to be able to grab a flare off of your MT-healer should the need arise) The goal is to get the lock out there all by his lonesome. He'll be tanking Astral Flares away from everyone. Everyone should be in position seconds from engaging curator.
If the lock wants - he can make a macro for /target astral - the locks job is to spam searing pain, and bring the astral flares into the middle of the room. This way they don't hurt anyone but the lock. The lock can keep this up and you can range the astral flares down before the next one is up. (Your caster/ranged dps should be using quick casts. Scorch spam for mages, etc)
From there on, it turns the fight from frantic, to relatively easy. - Only 1 person (max 2) should be getting hit by astral flares, you can heal the 'lock through the damage, and when curator evocates, make sure you take the last spawned add down FIRST, - THEN dps curator. As long as you have the damage enough to keep the astral flares under control, the fight is ezmode.
Note: Having warlocks throw up curse of doom about 1 min before his evocation, it can hit for 20,000dmg and severely help taking curator down before the 12 min mark. Cooldowns such as mage-pets, arcane power/pom/pyro, etc help as well.