There are 3 sets of T10 Druid Armor that come from adventuring in Icecrown Citadel that went live with WoW Patch 3.3:

• T10: 10-man
• T10.25: 25-man (Normal raid)
• T10.50: 25-man (Heroic raid)

The T10 can be purchased with Emblems of Frost with Ashen Verdict vendors that are in the Icecrown raid instance. Emblems are gained by grouping in random heroics through the LFG tool, killing Icecrown raid targets, the new Weekly Raid quest and a few small introductory quests for Icecrown 5-mans.

The T10.25 can be purchased by turning in your T10 piece plus a Vanquisher's Mark of Vindication which drops from raid bosses in Icecrown Citadel on 25-man Normal mode.

The T10.50 can be purchased by turning in your T10.25 piece plus Vanquisher's Mark of Vindication (Heroic) which drops from 25-man raid bosses in Icecrown Citadel on Heroic mode.

So all raiders who want the top level gear must first get the earlier versions. Welcome to the new progression.

If you don't raid, you can also purchase T10 level gear with Emblems of Frost from the Frost vendor Magistar Arlan in Dalaran.

Druid T10 10-man gear

The 10-man gear (iLevel 251) can be purchased with Emblems of Frost: 60 for the shoulder and gloves, 95 for the head, chest and pants.

• Balance: Lasherweave Regalia
  • Lasherweave Vestment
  • Lasherweave Trousers
    
  • Lasherweave Mantle
  • Lasherweave Cover
    
  • Lasherweave Gloves
    
• Feral: Lasherweave Battlegear
  • Lasherweave Rainment
    
  • Lasherweave Legguards
    
  • Lasherweave Shoulderpads
    
  • Lasherweave Headguard
    
  • Lasherweave Handgrips
    
• Restoration: Lasherweave Garb
  • Lasherweave Robes
    
  • Lasherweave Legplates
    
  • Lasherweave Gauntlets
    
  • Lasherweave Helmet
    
  • Lasherweave Pauldrons
    

Druid T10.25 25-man (Normal) gear

25-man (Normal) gear (iLevel 264) can be purchased by turning in your 10-man piece plus a Vanquisher's Mark of Vindication which drops from raid bosses in Icecrown Citadel on 25-man Normal mode.

• Balance: Sanctified Lasherweave Regalia
  • Sanctified Lasherweave Vestment
  • Sanctified Lasherweave Trousers
    
  • Sanctified Lasherweave Mantle
  • Sanctified Lasherweave Cover
    
  • Sanctified Lasherweave Gloves
• Feral: Sanctified Lasherweave Battlegear
  • Sanctified Lasherweave Rainment
    
  • Sanctified Lasherweave Legguards
    
  • Sanctified Lasherweave Shoulderpads
    
  • Sanctified Lasherweave Headguard
    
  • Sanctified Lasherweave Handgrips
• Restoration: Sanctified Lasherweave Garb
  • Sanctified Lasherweave Robes
    
  • Sanctified Lasherweave Legplates
    
  • Sanctified Lasherweave Gauntlets
    
  • Sanctified Lasherweave Helmet
    
  • Sanctified Lasherweave Pauldrons

Druid T10.50 25-man (Heroic) gear

25-man (Heroic) gear (iLevel 277) can be purchased by turning in your 25-man (Normal) piece plus a Vanquisher's Mark of Vindication (Heroic) which drops from 25-man raid bosses in Icecrown Citadel on Heroic mode.

• Balance: Sanctified Lasherweave Regalia (Heroic)
  • Sanctified Lasherweave Vestment (Heroic)
    
  • Sanctified Lasherweave Trousers (Heroic)
  • Sanctified Lasherweave Mantle (Heroic)
  • Sanctified Lasherweave Cover (Heroic)
  • Sanctified Lasherweave Gloves (Heroic)
• Feral: Sanctified Lasherweave Battlegear (Heroic)
  • Sanctified Lasherweave Rainment (Heroic)
    
  • Sanctified Lasherweave Legguards (Heroic)
    
  • Sanctified Lasherweave Shoulderpads (Heroic)
    
  • Sanctified Lasherweave Headguard (Heroic)
    
  • Sanctified Lasherweave Handgrips (Heroic)
    
• Restoration: Sanctified Lasherweave Garb (Heroic)
  • Sanctified Lasherweave Robes (Heroic)
    
  • Sanctified Lasherweave Legplates (Heroic)
  • Sanctified Lasherweave Gauntlets (Heroic)
  • Sanctified Lasherweave Helmet (Heroic)
  • Sanctified Lasherweave Pauldrons (Heroic)

T10 Set Bonus

Restoration

• 2P Bonus – The healing granted by your Wild Growth spell reduces 30% less over time.
• 4P Bonus – Each time your Rejuvenation spell heals a target, it has a 2% chance to jump to a new target at full duration.

Balance

• 2P Bonus – When you gain Clearcasting from your Omen of Clarity talent, you deal 15% additional Nature and Arcane damage for 6 sec.
• 4P Bonus – Your critical strikes from Starfire and Wrath cause the target languish for an additional 7% of your spell's damage over 4 sec.

Feral

• 2P Bonus – Your Swipe (Bear) and Lacerate abilities deal 20% additional damage and the cost of your Rip ability is reduced by 10 energy.
• 4P Bonus – Your Enrage ability no longer decreases your armor and instead decreases all damage taken by 12%, and the periodic damage done by your Rake ability can now be a critical strike.

Blizzard has put a preview of what the new armor looks like.

T10 Druid Relics

Tier 10 relics for Druids. They can be purchased for 30 Emblems of Frost from Magistar Arlan in Dalaran.

• Balance: Idol of the Lunar Eclipse – Equip: The periodic damage from your Insect Swarm and Moonfire spells grants 44 critical strike rating for 15 sec.  Stacks up to 5 times.
• Feral: Idol of the Crying Moon – Equip: The periodic damage from your Lacerate and Rake abilities grants 44 Agility for 15 sec.  Stacks up to 5 times..
• Restoration: Idol of the Black Willow – Equip: The periodic healing from your Rejuvenation spell grants 32 spell power for 15 sec.  Stacks up to 8 times..