Val'anyr, Hammer of the Ancient Kings

The legendary mace, Val'anyr, Gavel of Ancient Kings, has been added with patch 3.1. It is assembled from 30 fragments. Each Fragment of Val'anry is bind-on-pickup (BoP) and will most likely drop from raid bosses in Ulduar. Val'anyr is restricted to Paladins, Priests, Shaman, and Druids, so it is likely to be a healing weapon.

Shadowmourne is Next Legendary
The next legendary will be a 2H Axe from Icecrown Citadel. The site http://shadowmourne.com/ has more details and a photo.

World-first Val'anyr formed
Snuggleme of Avant Garde on Kil'jaeden has formed the first Val'anyr! Snuggleme seems to have disappeared, but Aethra of The Afflicted was the first member of the Horde on Greymane to complete Val'anyr. Lyssan of Final Stand on Duskwood has formed Val'anyr as of October 2009!

Proc Explained in Detail
Bornakk, an official Blizzard poster, has explained the Val special ability in detail:
"We have received many questions about how the proc works on Val.anyr, the Hammer of the Ancient Kings. While we originally intended for this effect to be a mystery, we realize that guilds now know what the tooltip on the proc says without necessarily knowing the details on how it works. This leads to situations where a healer may not know if assembling the hammer is worth it for them (hint: it is), and perhaps even worse, a misinformed leader may not think you deserve the hammer (hint: you do).

Players also wonder if the proc makes the item deserving of its legendary status given that the stat allocation is normal for items of its item level (Hint: it does).

The effect reads "Your healing spells have a chance to cause Blessing of Ancient Kings for 15 seconds allowing your heals to shield the target absorbing damage equal to 15% of the amount healed."

The way this works is that when the proc happens (which is a 10% chance whenever a hot or direct spell heals, with a 45 sec internal cooldown) you gain a buff (the Blessing) on yourself. Now all of your heals for the next 15 sec cause an 8 sec damage shield. The shield stacks with itself. It includes healing done by subsequent ticks of existing hots on the target. Note that the spell has to actually heal, so hots ticking on a fully-healed target cannot cause the proc. However the shield is based on the size of the heal itself, not the amount healed . i.e. 100% overhealing will not proc the Blessing on the healer, but the shield itself includes overhealing once the Blessing is active. The shield can grow to a maximum size of 20,000 damage absorbed.

Example 1: A paladin casts Holy Light for 10K on the tank, which partially heals her. The Blessing procs, so the paladin.s Holy Light immediately causes a shield on the tank which will now absorb 1500 damage. The tank dodges the next two hits, so no damage is absorbed. The paladin then casts another heal for 8K, but only heals the tank for 600 before she is at full health. The shield is now at 2700 damage absorbed (1500 + 1200) for 8 sec.

Example 2: A druid casts Rejuv on the tank, healing her. The Blessing procs on the druid on the second tick. A shield is applied to the tank which absorbs 15% of the amount healed by that tick and each remaining tick of the Rejuv. If the druid also gets Lifebloom and Regrowth on the tank while the Blessing is up, then those ticks also contribute to the shield. If the shield goes down because the 8 sec duration expires or it absorbs that much damage, it can go up again as long as the Blessing lasts, which is 15 sec."

Ghostcrawler has posted some extra info on the proc:
"1) If you are lucky enough to have two hammers in your group, then they will both contribute to the same bubble.

2) It should work as you would expect with PW:Shield and similar effects. Specifically, the damage should work through one shield and then the other. I don't know off the top of my head which one is used first. Sometimes we have edge cases with multiple absorbs like this that we will need to solve as they arise. (To be clear, PW:Shield will not proc the blessing or the bubble though, because it does not heal.)

3) If you have the blessing (i.e. you caused healing and the proc occured) then overhealing will count towards the bubble. Hots that tick on a target will still contribute to the bubble. You can also choose to switch to a direct heal if you don't have enough GCDs available to get all of your hots up before the blessing fades. The confusing part here is that hots that don't heal won't cause the blessing (we didn't want you fishing for the bubble before a pull by constantly healing the tank, though I suppose you could if your tank was injured). But once the blessing is active, then all of your healing spells will contribute to the bubble even if they do no actual healing.

We'll leave it to you guys to theorycraft out if you think the hammer is marginally better for one class than another. Some players were speculating before this announcement that the bubble only applied to one spell, which would definitely favor Holy Light. We implemented it the way we did to make sure the other healing classes could still get juicy bubbles while the blessing was active (which is 15 sec)."

Val'anyr Item Details released on the public armory! Here are the stats from the official WoW Armory:
Val'anyr, Hammer of Ancient Kings
Binds when picked up
Main Hand   Mace
93-298 Dmg
(108.8 damage per second)   Speed 1.80
+52 Stamina
+54 Intellect
Durability 125
Requires Level 80
Equip: Improves critical strike rating by 47
Equip: Improves haste rating by 46
Equip: Increases spell power by 587
Equip: Your healing spells have a chance to cause Blessing of Ancient Kings for 15 seconds allowing your heals to shield the target absorbing damage equal to 15% of the amount healed.
"The power of creation courses through this weapon."

Patch 3.1 is live! Start your 25 man Ulduar raids. :) The fragment appears to be a 100% drop. On three of three confirmed 25 man, normal mode (all towers destroyed), Flame Leviathan kills, a fragment dropped. UPDATE: It apepars the raiders were lucky that night. It seems to have closer to a 15% drop rate, so you can expect one or two per full Ulduar25 run.

For all healers! Ghostcrawler, a Blizzard employee, has confirmed that they intend Val'anyr to be useful for all healing classes. The known shield proc looks especially strong for Disc Priests.

It's for all healing!
The recent PTR patch has confirmed that Val will be for healers. Here's the equip effect:

Your healing spells have a chance to cause Blessing of Ancient Kings for 15 seconds allowing your heals to shield the target absorbing damage equal to 15% of the amount healed.

There's always the chance that there will be alternate versions for DPS, but right now it looks like a healer mace.

Assembled by defeating Yogg-Saron
Once you have the 40 fragments, you'll get the quest Ancient History (#13622):

Bring the Shattered Fragments of Val'anyr to the Archivum Console in the Archivum in Ulduar.

The pieces fit together to form an elegant hammer. Its construction appears to be at least partially Titan in nature.

The console inside the Archivum might have some information regarding this artifact.

Then you'll have to assemble Val by beating Yogg-Saron. The quest is #13629:

Throw the Shattered Pieces of Val'anyr inside Yogg-Saron's exposed brain and defeat Yogg-Saron to recover the Reforged Hammer of Ancient Kings.

The Archivum Console has hinted at a possible way to rebind the fragments of Val'anyr: you must get the fragments inside the physical form of the being known as Yogg-Saron.

It sounds like a long shot, but for an artifact of such power you think the risk might just be worth it.
The quest reward is 42 gold.

Drops from hard mode raid bosses
The fragments will most likely drop from hard mode raid bosses. Valnoth (a blue blizzard poster) has stated: "Hard mode rewards will be the best in the game." [ref] Do you think there's any connection between the names Valnoth and Val'anyr? ;)

Multiple Maces
This icon matches the 3D weapon model for Val'anyr:

There are also several other similar mace icons being added in the patch. Some of these icons are probably for the unassembled Val'anyr used while completing the final quests to make it. However there are 10 other new mace icons, so there are probably multiple versions of the Val -- one for each class that can use it:

The spell used to combine the fragments is 62812 : Forming Val'anyr, Gavel of Ancient Kings. Combines 40 Fragments of Val'anyr to form the Shattered Fragments of Val'anyr.

Currently the fragments are listed as unique(30), however 40 are required to assemble the Shattered Fragments of Val'anyr and start the quest for the legendary weapon. This might be to prevent its creation on the test servers.

We'll be adding more information here as it becomes avaialble. Stay tuned! You can follow us on twitter. If you have any information we've missed, please email us at web@mapwow.com

The fragments of this ancient hammer glow with a cool, soothing light.

Here's a video of the spinning/reforming animation of the mace and a video with the center particle animation:

MMO-champion.com has a screenshot of 3d model of a paladin equipping what might be Val'anyr:

and a screen shot of what the fragment tooltips might look like: