Valithria Dreamwalker

Valithria is an upside down fight.  You need to heal her from 50% to 100% to "beat" her.

The quick and dirty version is that a group of healers go into the portals to get healing buffs then come out and heal her while everyone else manages the adds.

Shopping list:
2 tanks
6-7 healers (3-4 portals, 3-4 raid healing)
DPS - including 1-2 zombie kiters

The Portal Team
The 3-4 healers in the healing team (and everyone else with any spare GCDs) start spamming Valithria as soon as possible and do not stop.  Put your best single target healers in the portal team, eg pallies. Resto shaman really excel at this with their chain healing spam.

Valithria will put up green blobs on the ground saying "I have opened a portal into the dream".  These blobs will eventually become clickable.  The portal team needs to be ready and in range to get in them as soon as possible.

Once in the dream you have 15s to collect green blobs.  You need to jump up off the ground and fly around collecting green blobs in the sky.  It is a good idea to allocate each healer a general area for them to collect their own blobs so they don't try to grab each others accidentally.  Left, Right and Front works for us.  It is useful to know that the blobs have an aoe effect and if someone else pops one and you are in range, the buff will also get applied to you. 

The blobs are tricky little suckers - not only are they small, but they float around.  Their radius of exploding is very small, you really have to go right through the glowing blob in the middle.  I highly recommend mouse turning for this phase.  Try to pre-plan your run so you collect as many blobs in as short a time as possible.  Each time you colect a blob your stack timer refreshes.  Obviously, the the idea is to keep as many stacks on yourself as possible.  The timer is 35s.  In order to keep this as up as possible, watch your dream timer on your buff/debuff list and TRY to pop a green blob JUST before you get spat out into the real world again.

Again, when you are out in the real world your number 1 priority is to get as many heals onto Valithria as possible, and if you have splash heals, splash them around as much as you can.  Bacon, chain heal, LoH (when you have 20+ stacks) all those special move heals which do lots of healy goodness - high HPS get them out and use them.  Heals on CDs, try to keep once per fight heals to the end when you have high stacks.

AAAAAADDS!
This is very stock standard "manage the adds" section of the fight.  You can go read up on the abilities of each add yourself, they are not really very difficult to understand.

The short version:
Get someone kiting the zombies away from the raid.
Kill blazing Skeletons as soon as you see them and with extreme prejudice (Lay Waste hurts a lot)
Try to gather the adds on top of the suppressors to the left and right to take advantage of aoe effects.
Interrupt the archmages
Avoid the columns of frost
Tank the aboms
Kill everything as fast as possible.

Honestly, that's it.  Keep the adds under control, get your stacks as high as possible.  Win.