The latest changes to patch 3.3 on the PTR. For a full list go here.

General
Meeting Stones: To use any Meeting Stone, it is only required that the character’s minimum level be 15. There is no maximum character level requirement for any Meeting Stone.

PvP
Battlegrounds
All level 71-80 Battleground daily quests will now award 25 Arena points in addition to their current rewards.
Wintergrasp
You must now have the following ranks to build or pilot siege vehicles:
Rank 2: Build/pilot Catapults.
Rank 3: Build/pilot Demolishers.
Rank 3: Build/pilot Siege Engines.

Death Knight
Army of the Dead: The cooldown on this ability has been reduced from 20 minutes to 10 minutes. Army Ghoul damage dropped by 50%. Cannot be used in Arenas.
Raise Ally: The cooldown on this ability has been reduced from 15 minutes to 10 minutes. Cannot be used in Arenas.
Rune Strike: Threat generated by this ability increased by approximately 17%.

Mage
Fingers of Frost: This talent now triggers immediately on casting a spell rather than being delayed until the spell strikes the target.

Paladin
Divine Intervention: Cooldown on this ability has been reduced from 20 minutes to 10 minutes. Cannot be used in Arenas.
Flash of Light: This spell no longer causes a heal-over-time effect unless the player has the Infusion of Light talent.
Lay on Hands: This ability now places Forbearance on the target and cannot be used on a target with Forbearance.
Infusion of Light: This talent now causes the paladin’s Flash of Light spells to heal the target for 50/100% of the Flash of Light healing amount over 12 seconds.
Aura Mastery: This effect of this talent has been reduced in duration to 6 seconds.
Sacred Shield: The damage absorption effect from this ability now triggers only once every 30 seconds.

Shaman
Earth Elemental Totem: The cooldown for this totem has been reduced from 20 minutes to 10 minutes. Cannot be used in Arenas.
Fire Elemental Totem: The cooldown for this totem has been reduced from 20 minutes to 10 minutes. Cannot be used in Arenas.

Warlock
Inferno: The cooldown on this summoning spell has been reduced from 20 minutes to 10 minutes. Cannot be used in Arenas.

User Interface
Group Disenchanting Option: In addition to rolling Need or Greed on items, players now have the option to elect for an item to be disenchanted if an enchanter of the appropriate skill level is in the group. Disenchant works exactly like Greed except if a player wins the Greed roll, they will receive the disenchanted materials instead. Players who choose Need will always win the item and will always beat those that choose Greed or Disenchant.

Remember, this is only PTR, not all these changes will go live.

Two new mounts have also been added: The Big Love Rocket, which presumably will be part of the Valentine’s Day event, and, wait for it lore fans… Invincible.

If you don’t know, Invincible is Arthas’ horse, first in life, and then raised from the dead when he became a Death Knight.

Both mounts will change speed/flying depending on the rider’s location/skill.

Update: mmo-champion has a pic of the Invincible model: http://static.mmo-champion.com/mmoc/images/news/2009/october/flyinghorse_updated.jpg